The rumor I had heard was it would be Studio Bones who would handle Season 3. Sure, it wouldn't be as god tier looking as S1 by Madhouse was, but still would be a major improvement over what we got with Season 2. But I guess the hype is dead for me now.
JC Staff just don't seem to excel at animation in terms of action from what I've seen, the sole major exception from them I know of is what I've seen of A Certain Scientific Railgun.
At this point, if I want to know what happens next in OPM, I think I'll just check out the manga. At least the mangaka's other work, Mob Psycho 100, got all of its seasons done by Studio Bones with pretty damn good animation from what I've seen.
It was never going to be a fair comparison. Season 1 almost had the quality of an OVA. Anything afterwards was going to be a step down unless it was from the same studio with the same passion.
Exact opposite for me: the second season looked bad, I stopped after one episode and never looked back, especially after coming directly from season 1. Madhouse just set the bar too high.