Well, one mechanic that annoyed me is the standard TES magical merchants that can tell if any common item has been stolen from anywhere on the planet, so if you want to sell them you can either camp out in the thieves guild over and over selling a little at a time, or burn perks to fix it.
That has no effect on actual character power level as if you want you can still sell everything without it, you just have to waste time waiting. The only thing it accomplishes is to annoy the player into jumping though hoops that make no sense. I would understand if a merchant knew something in his town was missing , but mystical knowledge that the dagger you enchanted was stolen a week ago across the world is a bit silly.
"Say... i heard a peasant who I have never heard of or met lost a butter knife that looked a lot like that one.... THIEF!"
"but sir... you just bought six other identical knives from me... what is wrong with this one..."
"I can tell... you stole it... get it away from me!"
"How about if i go craft daggers for a while so you like me more?" (craft daggers, level, buy a perk unrelated to what you did to level)
"Hello, Can i sell you this butter knife?"
"Sure... that is a fine butter knife"
"I stole it"
"Its all good man"
Another poor mechanic is the way you learn alchemy ingredients. You can either randomly combine them over and over and pray you figure them out, or, as most people will do, tab out and look up all the combos when you are doing alchemy, then trick the game into letting you tab back in so you can learn the recipes. I mean really.... come on. Even using the tab out and look method takes eons to free up all the ingredient info. To fix this issue you can sink points into a skill that does nothing but remove a poor mechanic. They should have just stuck with the oblivion method of letting you know more of the affects as you raised your skill.
Lol anyway, it may sound like I hate the game, I don't, I am just waiting for the mods to start rolling in. That is when the real fun begins in a TES game.