I haven't seen Oblivion's dialogue yet, so I'll hold out on judging which is more interesting. Given that dialogue has never been the focus of TES, I'll be willing to bet you're right. Still, nobody ever really expected a deep dialogue exchange system for Persuasion to begin with (particularly since it would probably require all characters that speak with NPCs to be good at Persuasion, because it would replace a lot of standard dialogue trees and such). What most people expected was a repeat of Morrowind's system. Well, what we got is a repeat of Morrowind's system, only the dice roll result is more interactive.
Still, I think this's off-topic for this thread, so I'll let it go