I would personally like to see a lot of things changed in the net installment. Sorry if i repeat any already said changes, but this topic was pretty much one big tldr case. First off;
More Weapon variety: In oblivion, you pretty much chose from Swords or axes/maces if you wished to do melee combat, one of which being the obvious choice over the other. If you wanted ranged combat, you got Bows or staffs (i'm not counting ranged attack spells, I'll get to those). I'd really like to see a more diverse weapon pool. Incorporate more styles of weapons such as two handed items other than swords/axes (I.E. Halberds, Spears, melee use staffs, ect.) and weapons we have yet to see in a game like this (Flails anyone?) and PLEASE PLEASE PLEASE, make sure that when you go dungeon hopping you don't come out with 9 of the same "silver longsword" items. Show a little variety, maybe even a bit of weapon backstory? I'd like a mechanism where at lower levels, you don't know what your weapon is capable of. You could take it somewhere to get it examined, or level up in let's say, spellcraft for example, and learn for yourself. Same goes for armor. Looking at a sword shouldn't make it apparent that it does 30 shock damage. Additionally, where are the crossbows? come on Bethesda.
Better leveling system: When playing a game like this, what I look forward to is progress. I'd like to see a better leveling system in which, maybe at certain levels, you attain new features on your character (if you have so far specialized in spells, maybe your spells gain a distance on range, or a more potent effect). Additionally, You shouldn't be able to cast every spell under the sun at level one. The leveling system is supposed to show how your character has matured over the course of the game, and as fun as it is, I don't want to be able to beat half the game as a level 1 character.
An interesting alternative that i had thought of; during your first playthrough, you should be restricted to a preset "class". You can choose from a list of presets, yes, but you can't have as much customization from the get-go. After you beat the game, however, you can be rewarded by not only choosing your typical "seven major skills and two best attributes" but also what features and skills your character will acquire as you level up.
Example: first playthrough, you choose the battlemage class. Yeah, the battlemage has certain skills you'd like to change next time. You beat the game, high fives are exchanged, and then you restart, except this time the world is at your fingertips.
Another alternative: Perhaps you could unlock the skills and features that you can customize your character with only after you've seen them in a previous game. Your ES5 persona shouldn't know how to summon the dead unless he's spent a fair amount of time with some necromancers.
Side Notes #1: NO LEVEL CAPS. NEVER.
Skills: we've all said or heard a time of two that Oblivion needs more skill variety. Riding horseback is great, but not when a mud crab can track you down and kill your horse because your character can't reach down and hit it while riding. Necromancy would be a useful addition, as well as smithing (no, not armorsmithing which is a lot different than what i'm speaking of), I propose smithing be put into many separate skills; Armorsmithing, Weaponsmithing, Bow-smithing (haha), tailoring, staff-crafting, ect.
Side Notes #2: DUAL-WIELDING PLEASE.
Tell me what you think, I have many more ideas
