As long as the skills are useful for some gameplay advantage within the economy, combat, magic, social and navigation systems then I'm fine with more skills.
Thats the thing. Skills should all be really useful. Skills like Mercantile and Speechcraft are not as useful as other skills. Security is unnecessary because of the ease of the lockpicking minigame. I'm not saying consolidating all the magic skills or weapon skills into one skill. I'm just saying each skill should be useful. Consolidating can help this. But too much consolidating can just make a game just svck.
Like what is the point of having acrobatics, atheletics, security, or speechcraft in oblivion? Any player who picked this skill as a major skill is just wasting their choice. Its not enough for a skill to just have a little advantage.
One thing I would like to see is acrobatics and athletics consolidated. And make them actually useful like the ability to do some mirror's edge stuff (I know its a long shot, but it would be awesome). Maybe NPCs that are good at it can too.
Speech was pretty useful in Fallout 3, but not enough. They should make it even more useful in TESV. A character with maxed out speech should be able to talk their way out of almost everything.
Also, kill the lock minigame. But give players the ability to bash stuff, only some doors/locks are too strong, or if you bash stuff you have a chance of destroying the items in the container (i.e. kotor 1 or 2, cant remember). Also NPCs will notice you making a lot of noise. Picking a lot should be based almost completely on character skill.
Bring back enchant. Expand the spell tomes thing to the primary way players learn/use spells. That way pure magic characters have some encumberance with spell tomes (maybe for powerful spells they have to keep the books on them to use). No more spending a ton of gold to have a 'spell vendor' teach you a spell. Instead spend it on books (spell tomes).
More fluid combat also. Make it more realistic like swordplay then finishing stab. You shouldnt be able to just slash someone with heavy armor to death with a dagger. Also heavy armor should offer more protection but decreased mobility. Light armor, the converse. Bring back unarmored for super mobile characters. Let them dodge out of the way of stuff (maybe add a dodge portion to the block skill?). Bring back spears, crossbows, and throwing weapons. Make two handed weapons actually useful.
Make NPC interaction even better than it was in Fallout 3. This is one of the areas that I think the elder scrolls has lagged behind in for some time when compared to other rpgs (mass effect is getting old now).
Make uber stuff to do for uber characters. If someone is really high level, then maybe they can fight a small army. Also more epic rewards, like becoming the count of a city or something (I liberated a whole city (kvatch) and all I got was some stupid enchanted chainmail shirt?! why bethesda why?!). If you save the empire they should reward you with a feifdom, not just some fancyshmancy armor.
Thats all I can think of now...