IMO: Yeah Escanor probably should've won - reasons being that Melodias didn't have full control over his powers - remember how he had to do a training arc with the Druids prior to fighting the Commandments? I 'member. So it doesn't make much sense to me how he was able to assume his full power form with no repercussions. I guess Nakaba keeps forgetting what he was and wasn't able to do at certain periods of time. Maybe Melodias simply took Escanor by surprise, but if that was the case it could've been better if Escanor had a deep rooted fear of demons so that it would've felt reasonable for him to be hesitating even briefly and getting KO'd.
To me the series peaked when they were forced to save a kidnapped Elizabeth. The end of that arc was pretty... bad - but the build up for the arc and a majority of the arc was 10/10
Problems started arising afterwards - characters acting weird. Strange direction and choices. Inclusion of power levels, training arcs, long ass flashbacks, lack of a traitor in the 7DS, fucking Gowther mindhacks causing Aizen plot points because 'lul memory wipe', etc etc
Let's also not forget how the main villain - the guy who's been fighting for the last fucking 60 someodd chapters - the Demon King, is entirely lackluster. Which he's also the main villain for the ENTIRE second half of the manga after Hendrickson, and the ball is dropped immediately with him. We have no real motivations or anything. I just don't care about this character. And hell most of the Commandments were the same way.
It also didn't help that the 7DS started to also slowly get drug through the mud, with pretty lackluster backstories. I think we got spoiled by having Ban's so early on that we expected crazy shit out of the rest of them, but then everything that comes afterwards just feels subpar in comparison. We also had Nakaba have every fight come into pure fighting. Why introduce these wonky Commandment rules if every time it just comes down to beating the shit out of each other.