With Riker even in S1 they didn't want to write him like his premise.
At the beginning they tell us he's the guy who likes to have fun and amuse himself, the big playboy risk taker.
Good idea, although they never once wrote an episode where he came off like that.
Season 1 Riker is pretty much a clone of Decker (TMP) anyway. Which is no wonder, since he was actually based on Decker.