yea but if you could use speech checks only if your speech skill is high enough, how can you increase your speech in the first place? this is some serious dilemma behind designing this game. I'm not really sure if there's a correct solution to this problem, honestly. Mass Effect is just linear with paragon and renegade options. In Skyrim, you can talk to almost everyone and you won't be having meaningful conversation all the time. Speech is a game mechanic that gets you stuff in Skyrim as opposed to Mass Effect which uses it for story-telling. So I guess mini-game is somewhat necessary but Fallout shows us that you don't really need a minigame for speech checks and it could be used to define your character.
Skyrim will probably take Fallout's example. Since your skills increase through practice, there's gotta be many trials to increase it. Fallout obviously had limited speech checks but it didn't matter since those speech checks are very useful for quests and you can just distribute points to speech every time you level up. I'm really curious how Skyrim is going to tackle this issue... they don't cover on speech much, unfortunately so we won't really know how exactly it'll work out. Judging by some reveal speech perks, there's gonna be some percent chance behind speech. I think it would be nice if it was 100% success rate if your speech skill is just high enough, rather than like 97% in fallout 3. I raged hard when I failed that one.