As I've pointed out before, it's just a retread of stuff from previous seasons, has been zero surprises because they literally repeating themselves, and it's boring because no surprises.
The big bad has bullshit levels of foresight and knowledge of things he couldn't possibly know to the point he isn't believable or interesting, a character with no flaws is boring, and that is what he is. Marty Sue.
Season 3 and 4 were dire, but if standards are low enough to call them 'not that bad' I can see why season 5's mediocrity of repeats is getting praise.
They weren't that bad, at all. Rewatching them S3 started off slow but that was because of the Legends set up, the same problem that hindered Flash. After that it was alright, nothing too bad but people wanna complain about Olicity and everything they see as possibly wrong.
Season 4 is fine, it's not bad, it's not great, I had no real complaints with that season except for the fact that it's just Season 2 without Slade. A part of Season 2 that is overstated, his motivations were awful, those flashbacks did him no favors till he got the Mirikuru. He was a walking deus ex machina if you wanna complain about Chase. And I liked Slade.
Season 5 was really good, period. In a vaccum it was good, ignoring any past shows, shit was good. Character development, writing of story, it was solid. And to say Chase had no flaws? Okay, sure.