Oblivion's Speechcraft minigame should not be removed. It should be burned, flayed, staked over a nest of fire ants, and the carcass left there in the next game to rot as a constant reminder never to do that again.
It failed on so many levels, it amazes me. First, it had no real connection to your character's speechcraft skill. Whatever your skill with the minigame was, THAT's how good your character was, no matter if they had a 100 or a 5 skill in it. Second, it didn't bear any resemblance to even a crude caricature of "speech", which at least the lockpick game did. The stupid wheel wasn't even an abstraction, it was a totally unrelated "substitute" for a conversation. Third, what sane person would alternately Taunt, Admire, Intimidate, and Boast in the same conversation? Even if the listener didn't run away looking for a healer or a guard, they most certainly wouldn't LIKE you for it. Fourth, it was buggy. Not only didn't it work in a rational manner, it didn't even work properly in its intended irrational manner.
Bethesda, PLEASE reprimand whoever was responsible for implementing this disaster.