Ricochet is different, and when something is different it either gets praised or hated. Ricochet is a different style of game you're used from Valve, specificly the popular games back 'n the day like HL and TFC, and so it got lost in the violence of HL and its mods. Which is quite understandable really, I never used to play Ricochet either, for it is also a small and basic game.. but still, I know for fact some people never really gave Ricochet a fair try for silly reasons like not being able to jump by yourself.
About the game being confusing, I honestly can't believe that, because it isn't a complicated game and if you're somewhat of gamer you would understand how it works in less than a few minutes. But just because you understand how it works, doesn't mean your good in it, and I think many people see those two things as one. The thing with ricochet is, while its basics are simple, it is hard to master as a whole (good strafe jumping, aiming and prediction). However, isn't that with every game? You'll just notice it more quickly with Ricochet for the game is hectic, fast and small.
For about half an hour, you if have a decent number of players
I'd have to agree with that, it isn't really a game for long sessions (more than an hour), but to get some fast games going fraggin' round it's just right.
EDIT: omg, what a bunch of text. Heh, I got carried away I guess.
Tl;dr - Ricochet is awesome for what it is, if you just give it a fair chance.