I never played Arena, so these are ideas that I feel should be retained from previous Elder Scrolls games except Arena.
DAGGERFALL
1. 2D NPC's so when you walk around them in a circle they are always facing you. Just kidding.
2. Random generated quests. I would love a portion of the side quests to be randomly generated. I'm not saying we want every other NPC to offer a random quest. But perhaps there is a way for the game to keep track of the last quest completed so it will remove it from the random list until so many additional random quests have been completed then it gets put back in. So say you clear out rats from Sally Simpson's attic. Rat extermination will not be offered again until you've completed, say, three additional quests from the random pool. Then rat extermination is put back in. Something like that. I feel that random quests add to the depth of the game, give the adventurer a reliable means of income, and just give it a touch of nostalgia. Random quests would also be a way for fans of hard-core level scaling to get their fix. As you go up in level and gain notoriety for being a bad-*ss adventurer the random quests you're offered could come from a different, higher level pool. Some people will still want you to clear their actic of rats, but others will see you and say, "well, someone like you is def suited for my issue. Seems that a minitaur has decided to wander about the graveyard outside of town and ever since then I've not been able to visit my mother's grave." Not exactly killing a rat.
Much of what I like about Daggerfall was actually implimented very well in Morrowind, so I'll move onto that game.
MORROWIND
1. More static world. There may have been some form of level-scaling in Morrowind, but it was either far, far more subtle, or it was only for certain places in the game. Whatever the case, it was more static than Oblivion, and greatly added to realism for me. Without heavy-duty level scaling the world didn't hinge on my every level gain. It seemed like a more real place, and not one that simply existed for my betterment. Replayability is harmed by extensive static content, but that is why there is a construction set. If Modders don't have to spend a year just fixing the game, they can jump right into adding content. Imagine the amount of quests, and treasure the OOO, and Frans teams could have come up with if they didn't have to spend years getting rid of, or massively tweaking most of the level scaling.
2. More varied world environment. Morrowind was a place that had arid deserts with sand storms, bizzare coastal enclaves of wizard towers, and more traditional temperate zone cities like Balmora (THE BEST CITY EVER IN AN ELDER SCROLLS! Well, that's my opinion). Morrowind had mountains that you couldn't climb over unless you had mad skills, or some levitation potions
steep ravines, strange ruins, etc... It did not have real forests, however, and that is something from Oblivion that I'd like to keep. The atmosphere of Morrowind was more...atmospheric to me. The poorer draw distances, coupled with rainstorms generated this really cool fog/haze that added something for me. Sand storms I've already mentioned, rain, snow in solsteim (spelling), all sorts of things that added to the atmosphere.
3. Levitation potions.
4. More armor/clothing slots. This has it's own thread now, and rightfully so. Daggerfall and Morrowind both had more armor slots, and the ability to paperdoll your PC with both clothes and armor in layers. This was something that wasn't broken, and didn't need to be fixed. PC's want to wear cloaks over armor. If that is not put back in then we know the devs do not read, or do not care, what is written in these forums. I can't find one person who is against having cloaks and robes over armor. I know people who are indifferent, but there are massive numbers of players who want that put back in. It adds a nice layer of role-playing and immersion to the game. Sometimes the little things are what matters.
5. Put all missile weapons back. I'm indifferent to this, but I know of many, many who are definitely not indifferent. It's again, one of those things removed, probably for technical reasons that really harmed the game play for a lot of folks. For many people this harmed their experience as much as the nerfed armor did for others.
6. Means of Fast-travel. Let's get back to fast-travel being a means of transport that is intrinsic to the game world itself and not a "meta" travel method. By that I mean, lets have things that are part of the game world itself like the Mages Guild was in Morrowind, move you around rather than a menu option. Let's get back to recall like spells, and so on. I want to be able to go back and forth sometimes between distant places, but it should be via 'in-game' means. The game world of Oblivion felt smaller than it was partly because of this unfettered fast travel. It was also just smaller to begin with which brings us to...
7. World Size. gamesas likes to say that though the geographical world of the elder scrolls is shrinking, the detail is growing. Well I respectfully disagree. It's definitely shrinking, but the detail? I'm sorry but with dungeons all being virtually the same, relying on level lists for loot and enemies, and unlimited fast travel to all the major cities in the game, makes the world seem small and not as detailed. I understand that for a game world the size of Daggerfall, you rely almost fully on random everything. That is an extreme we need not go to. But what if we went back to a land size like that of Morrowind, but with detail and content newer computer technology could bring us? I'd say that most people are not using the same machine they were using back in 2002 when Morrowind was out, nor even the same exact machine we were using back in 2006 when Oblivion came out. I'm sure the avarage player will be using a much better machine when TES V comes out someday, than what we had for Oblivion. You know how it is. You built a kick-a** computer and in less than two years Best Buy sells one for $599 that is the same or better than what you built for $1000. But I digress. Morrowind size world.
OBLIVION. (Yes I like things about Oblivion too)
1. Graphics. Hey, the graphics in Oblivion were beautiful and detailed. Texture mods made them even better. I would be warry of making them even more photo-realistic, however, if it's going to continue to rob us of crossbows, and cloaks over our armor.
2. Draw distance. I loved being able to see the land spread out before me in a really nice vista. I think there should be days, however, where the draw distance is greatly reduced because of weather patterns, humidity, smoke, etc... it'll add to immersion.
3. Physics. Objects that moved in realistic ways was more advanced in Oblivion. I liked how chains, and buckets and other objects moved.
4. The idea of AI. While the AI actually was nothing as awesome as they were trumpeting before the game came out, the idea of it is right on the money. It could potentially create a lot of random events that add tons to the experience. And please devs, save us the line that, "Oh it's there. It's just in the background and invisible to the player..." Well then whats the point? This is game afterall, why spend resources and time on things that are invisible AND don't effect our game experience. Morrowind had no radiant AI, but it was more fun to a lot of people. Some people loved Oblivion more than any game ever, but I guarantee it had nothing to do with this mythical Radiant AI. If they perfect the AI so we can see random events break out, then I'll smile and say, "wicked good AI"
5. Length, and imagination of some 'guild' quest lines. Particularly the Thieves 'gray fox' quests. That was really well-done. Whoever was responsible for that quest line should have been given a bonus and promoted. If all the guilds had quest lines like that Oblivion would have been better in my eyes.
NON-ELDER SCROLLS GAMES THEY SHOULD GO BACK TO FOR INFLUENCE LIKE THEY ONCE DID
1. Ultima. Ultima was the RPG that most influenced and intrigued Todd Howard. He should remember that. If you have never played Ultima 7 parts 1 & 2, get it from the Exult team online and treat yourself to an awesome living world with a great storyline. Since you may never have played prior Ultimas some of the stroyline may be confusing, but no matter. You'll understand what I'm talking about.
2. Wizardry. The grandfather of computer RPG games. In Wizardry you had NPC's going for some of the same goals that you were. It added a lot of replayability. Wizardry games are not for everyone (they're mind numbingly complex and difficult) but much could be gleaned from them.
IDEAS FROM MODS THAT SHOULD BE IMPLIMENTED
No way to cover all these but a few I liked:
1. More mutually exclusive guild/association quest lines. You should be able to join the blackwood company at the exclusion of whoever it was that wanted you to kill them. Fighters guild I think. Many examples of this could be implimented. It should be either really really tough, or impossible to join conflicted guilds and/or get very far up them. Perhaps it could be done but it should require a lot of imagination and a** kissing. This adds to replayablity.
2. Weather inside. The weather/atmoshere mods really helped immersion. Being able to hear a storm rage outisde the inn you are staying at just was really cool.
3. Illumination mods. Seeing light glow from inside buildings at night was sweet. Real light mods were awesome as well. They made candles, torches, and other means of illumination actually illuminate.
4. MMM. More and varied monsters are always a good idea.
My modded version of Oblivion is very close to what I was hoping Oblivion would actually be. If they could just come out with a game that didn't need as much fixing out of the box, I'd be thrilled.
Let me be clear here too. I don't want Morrowind II. I want an original storyline, new game-province, new NPC's, etc... I just would like it to be a game that nicely melds the best from the prior games and mods, and adds some new ideas as well.