Well, yeah, true - in the context of the whole Saga, RotS definitely stands out as having a... much clumsier feel to it.
Though, I think there's more discrepancy in style for the Saga than most.
I break it down like this:
IV-V have their "true" Star Wars feel
VI-I have the kiddy, plot-hole style
II has its own "Episode II" feel
III feels like a computer generated cartoon