That's your opinion.
For a series that's all about consequences, it's bad. Also it's simply frustrating how the show never makes any progress because of it.
Season 1: an armored titan! But we can't kill it. Let's kill the female titan instead - oh, we can't, either.
Season 2: yay, we got him-ah, so close! But let's try again-AH, he got away again. And he also took away Ymir, our just found new titan ally.
Season 3: we've got new anti-armor spears! Yay, he's dead! Oh wait, he's alive. But he's as good as dead, let's deal with Bertholt first- oh snap, Rainer is fully healed again.
That's where we're at. Just how many seasons will it take to make meaningful progress aka killing Rainer?! At this point in time I'd be half-satisfied if Levi really manages to kill the beast titan, but I'm not convinced that'll happen either 💁