I don't think the point of the riverboat was to be a thrill ride or boat adventure. That wasn't Walt's idea for, well, anything. It tells a story, just like ALL Disney rides and attractions do (or should). You learn about Mark Twain, and how paddle-wheelers navigated. You hear stories. You see scenes that tell the story of time. If you're simply there to be entertained and thrilled 100% of the time, perhaps Universal or 6 Flags is more up your alley.
I, for one, love the Riverboat and am sad that it may be down when we go in June. I could take trip after trip around the river, standing at the rail on the top deck, listening to the narrator do his spiel. But that's just me, I guess.