I think they should, but only if it's more interactive that Oblivion. I don't want to fork over my 1000 septims, then 'poof' im better. Maybe I pay them, then have to do something and upon completion get my skill point. LIke if I buy 1 Handed weapons training, I must duel someone with a 1 handed weapon. Then the higher your skill the harder the enemy. e.g. if your training from 10 to 11, its very easy. But from 95 to 96 is a very difficult battle. Some system like that, I dunno. It should at least take time out of the day and not be instant.
Something like this, at least some sort of minigame or other. Pay gold and do something "semi-difficult" and you raise your skill quickly, or go out and do it yourself slowly.
Voted they should be in. I don't really use them that much, but they are nice to have if you sometime need a very low level skill increased that is not easily increased.