Race - Race should be only include human, ghoul, and supermutant. Each primary race should have a selection of sub-races. Humans sub-races could include Vaultdweller, tribal, wastelander, or BoS initiate. Ghoul could include Glowing One, wasteland ghoul, sewer/underworld ghoul etc. Supermutants could include brute, behemoth, pure supermutant(supermutant from prime normal origins), etc. Robots should be out because in the FO universe AI could only take the form of a supercomputer such as ZAX or President Eden. Robobrains have organic brains and cannot even muster independent thought. I know the sub-races I have chosen seem limited but they lend themselves to many different appearance choices and backgrounds and would have race specific traits and characteristics. Fallout is about the grittiness of the fall of civilization and how the human race trying to pull itself back up from the ashes with its primary threat being itself.
Skill Progression -
Experience should be given based on skill usage not on kills. Maybe there could be several types of experience points. Using combat skills primarily gives Combat experience but gives a little in other types such as Survival, Science, or Mechanics. Using Survival skills gives mainly Survival experience but gives a little to Combat so that you may still defend yourself. How about this experience division Combat will be C, Survival will be S, Science will be Sc, and Mechanic will be M.
Combat gives 80%C/10%S/5%Sc/5%M
Survival gives 15%C/70%S/5%SC/10%M
Science gives 5%C/10%S/75%SC/10%M
Mechanic gives 10%C/5%S/10%SC/75%M
Not perfect but gives an example
Skills and Experience types -
Combat
Guns and armor etc, nuff said?
Survival
Scavenging, Foraging, Traps, Construction(for shelter etc) etc.
Science
Medicine, Computers, etc
Mechanic
Gunsmithing, Armorworking, Vehicles, etc.
Game Play elements =
Staying Alive =
I don't think that combat should be the core mechanic, it should be survival. Hunger, thirst, radiation and dealing with it. You should be able to starve or thirst to death. Sure you can take a slab of that mole rat and roast it over your fire or turn cannibal and eat the nearest escaped slave, but thats not guaranteed. Farming should be an option, as well as the hydroponics like in Adytum. And most of the water has become undrinkable from radiation and other contamination. Does it make sense to be that seasoned wasteland wanderer who does not need to wet his sand caked mouth? Not really. Radiation is an obvious threat in the post-nuclear world and avoiding and dealing with its effects are important. I don't know what kind of consequences for hunger and thirst could be, personally I think it should be several stages. Fatigue, weakness, visual anomalies, etc. gradually working its way towards death. Obviously people would hate permanent death, but what about dying from hunger or thirst caused skill loss, depending on whatever cloning system they use, maybe there wasn't enough nutrients in your body to maintain your skills on cloning. That sounds like motivation to stay well fed and hydrated.
Economy -
I know that bottlecaps are a core element to Fallout, but what if currency altogether was abolished? What it was left to the player base to create a form of currency? If they had several servers currency could easily vary server to server. One could be bottlecaps, the scorched remains of pre-war cash, the bones from your victims or human teeth, it could be several seemingly worthless things left in the wasteland. Or we could just barter who knows.
Combat -
I think it should be completely unnecessary, I think you should be able to scavenge old homes, bunkers, skeletal cites, wrecked cars etc.(Obviously you would want to be at least a little skilled with a hunting rifle to defend yourself) and in turn trade your finds to a craftsman in town who in turn fashions a nice suit of leather or maybe a pipe rifle and then sells it to the combat focused mercenary who gets his chest torn open by a deathclaw and now with damaged lungs goes back to that town to see the doctor who has to go back to that scavenger to get the supplies he needs to manufacture his medical supplies. Sure, some people want to be self contained and solo through the game, but what if the option was there to buy the food from the farmer that wants to farm and not run and gun rather than have to scavenge the empty wastes for it yourself? Not saying that combat people should be forced to depend on the non-combat people but that it is more convenient and time efficient to turn to those who have chosen peaceful ways. As far as PvP, I think it should be free reign, safety only in certain towns while other towns would need to hire mercenaries or build fortifications.
Shelter -
I think you should be able to post camp wherever the hell you want, as far as protecting your stuff? Well I don't think it should be a house no one else can enter, I think you need to set up traps, fortifications, hire guards etc. Or maybe you mosy on down the the local BoS and buy a high-tech lock of some sort for either your entire house or just the trunk in your tent you use to store the ammo you can't carry.
Mounts -
I do not think they should be limited to the high level characters. I think if you can scrounge up the parts or currency (whatever it may be) you can have a shiny(ish) new(ish) Corvega or motorcycle. I think the wasteland should be sprawling and that you should be able to find privacy in its massiveness that you can build your tent without too many worries of an errant griefer coming to rob you for fun if you are dumb enough to forget that lock.
Crafting -
I do NOT think that crafting should be the way to get a fancy version of a sharpened spear. I think it should be NECESSARY to obtaining almost ALL items. I think there should be maybe one store in the newbie area that sells a slingshot, hammer, and a shovel that's IT lol. But seriously I think that we should depend on that towns blacksmith for armor and weapons, or farming equipment, or whatever. And if you become skilled enough maybe you can join the BoS or Enclave and provide them with your talents in exchange for room and board.
Factions -
I believe that factions should be like no other MMO. I think they should provide towns with protection, form scavenging parties for mass profit, caravan guards, caravans, etc. Or maybe just patrol the wastes in the name of justice like the Regulators.
Research and Technology -
I think that you should be able to research new technology using old documents found in military and private research institutions. And you can either sell your findings or maybe just make a limited use blueprint copy in the way of EVE Online so that craftsmen can build and sell your discoveries.
Class -
I think your class should be whatever you want it to be. Maybe you want to scavenge collapsed buildings for chunks of metal and cloth for the local craftsmen to utilize. Or maybe said scavenger wants to be more of a risk taker and dive down that glowing hole in the ground to get some previously top secret files from a self realized AI so that that researcher can develop a new plasma rifle. Or maybe you want to be a mercenary to protect a town, or take on odd jobs to take out a raider band harassing the local populace, or the cannibals kidnapping children. Or maybe help protect that scavenger as he dives in that glowing hole, or join the BoS in their efforts to bring about peace or their war with the Enclave. Maybe you want to be the craftsmen that provides the equipment for them, or the doctor who heals the mercenary or treats the radiation sickness of the scavenger, or maybe the farmer that feeds EVERYONE.
I'm leaving out a lot because I'm tired, I'll come back and post later. Maybe