In the grand scheme of things when it comes to continuations of popular, old-school even, mangas/animes, at least I can properly say that Clear Card wasn't a complete waste of time and a systematic character assassination (at least everybody seemed pretty consistent with their old selves, imo and there was no crazy behaviors). Because, believe me, there's no shortage of that in other sequels. That being said, I kinda understand now why it left a lot of people with mixed feelings. I have my couple of complaints as well. Sequels are often hit or miss but, more often than not, they don't have much going onthat justify their existence. Clear Card had a lot of potential up to some point, I would say around 60~70 is where things start to fall apart bit by bit. Nothing extreme tbh but I wouldn't go as far as to say that I'm completely happy with the decisions. Then again, CLAMP has this little problem sometimes that after complicating a plot too much, their solution is to complicate more and hope for the best. And I feel like the plot would benefit more of having a proper villain. An actual proper villain. Not "oh, I troubled you but it was to help in the long run", because that would make this the actual third time that happens (though with Yue, it's a bit more complicated...). I had this faith within me but the writers had other plans and now it doesn't make a difference to complain too much about it.
But it's a solid sequel. Worth the development style of an already beautiful art style, cool concepts and an opportunity to see Sakura and Syaoran, and the others, just one last time. But if you want to pass, it's okay! You... well, you aren't missing too much, that's the bittersweet part.