I like Skyrim and think it has brought a lot of great new features to the series (I could just as easily make a list of what I think Skyrim did right), but I think it's also abandoned some good old features and failed to fix problems that have been with the series for over a decade. So anyways, here are some of my complaints. It would be lovely if someone at Bethesda happened about this post, since I intend this to be constructive criticism.
Big complaints
I hate the lack of attributes. Instead of having a ring that gives you +5 strength which makes all your melee attacks better and lets you carry more, now there're rings that give you like +40% damage with one handers. It's annoying because it's overly specific with its benefit, and overly powerful with its effect. Attributes are a core part of most RPGs for a reason. There's no reason attributes can't live along side perks like they did in Oblivion. Doesn't it sound satisfying to have a stealth character and invest in agility so you can jump off city walls like a ninja and take little fall damage where a big lug of a character would ungracefully fall to his death? Or how about investing in strength and having a higher chance to bash right through a weak character trying to block?
There's a general lack of balance in this game. The crafting skills are brokenly overpowered. Random stores sell amazingly powerful items if you're high enough level. You can get a 100% reduction on the cost of schools of magic. There's no limit to the number of potions you can drink, so you can win just by chugging potions. Grand Soul Gems can be bought with top level soul in them right from a common merchant. So on...
Being able to make your own spells was one of the best things about the Elder Scrolls in my opinion. I want that feature back.
Scaling. Do I even have to talk about it? It's like an RPG anti-thesis that keeps working its way into RPGs.
Health and magicka regenerate so fast that I found myself hiding behind rocks waiting for my health to return in the middle of combat as a regular strategy. Magicka regenerates so fast that one doesn't have to strategise.
I wish there were more armour slots. Each new Elder Scrolls game has fewer. What's next, head/chest/legs/feet/hands all being one slot? It's an RPG! Gearing up is a huge aspect. Instead of slowly finding good pieces of armour you can just find a good chest/leg piece and boom, you're halfway done. Or you can go craft one.
I feel like the game thinks I'm stupid. It holds your hand too much. For example, compare joining the Morag Tong in Morrowind to joining the Dark Brotherhood in Skyrim. I don't think the excuse "they're trying to make the game more accessible to casuals and children" is valid. I found and joined the Morag Tong when I was like 13, and I managed to beat the game without it refusing to let me drop quest items or kill quest NPCs. I don't see why advlts can't be trusted to figure things out. Why are there arrows and lines pointing you to exactly where you need to go? Has the human race lost its cleverness since 2002?
Small complaints
Dual wield is annoying. I'll cast a spell then switch back to my dagger but the spell will still be on my left hand so I can't block until I go into the menu and disable the spell. If you're dual wielding you either have to have the counter intuitive scheme where right click makes your left hand attack, or the uncomfortable (to me) scheme where right blocks and left attacks. As someone who doesn't dual wield any weapons, the feature just gets in my way. Perhaps there could've been a way to toggle it off.
Bows are perfectly accurate and can be used at point-blank range. The opposite would be more satisfying to me. It would also be nice if a camp of enemies would react faster and more appropriately to being picked off one-by-one from afar. Ranged is too easy.
I don't like being a special little snowflake who has access to a large arsenal of abilities only I can use. Shouts have loads of cool effects, I think it's a shame those effects weren't just spells available to both the player and NPCs.
The current fast travel system takes a lot of the adventure out of the game. I think there should be a balance between convenience (a travel network between the towns, teleportation) and adventure (having to actually go to your destination and explore).
Voiced dialogue really limits things. If dialogue was just text like in Morrowind it would be much easier to have better dialogue. An example of what I mean: some guy turns into a werewolf in front of me and the only dialogue option I have is “What was that?” even though my character was also a werewolf. It's pretty much impossible to have a voice recording of every possible bit of dialogue, so Bethesda just has everyone say less. I should've been able to say “I'm a werewolf too!” and then the NPC could react to that revelation, but no. Additionally, whenever mods have dialogue they either have to break the immersion by being the only NPCs who don't talk (in a dialogue system build around voice acting) or have custom voices which are usually low quality.
I didn't like the main quest much, but I probably shouldn't say why since it might be a spoiler.
The menus are clunky. In Morrowind one button brings up your inventory, character appearance, character stats, spells, and map. In Skyrim you only get to view one window at a time, and their designs are poor and cumbersome.
The bloom effect that makes everything get too dark for a moment if you look at the bright sky then down at the ground is weird and I don't like it.
Everything zooms out when you run. It's disorientating, especially when running in short bursts and the distant terrain keeps swooving closer and farther.
Dragons are almost as annoying as cliff racers.
I miss disposition. Even though Morrowind and Oblivion made it too easy to raise disposition and had too few benefits and disbenefits from it. I think there's a lot of potential in it for good game mechanics.
In Morrowind having a full Daedric set was a big deal. In Skyrim all you need is 90 smithing skill and some materials from your local merchants and you can have a full Daedric set easily.
Changing from third to first person isn't instant. How annoying in a fight.