Enel's combat stats are heavily underestimated due to Oda's poor planning, it's likely the story of Crocodile again.
Oda considered him as a minimum standard commander level, considering his hypothetical bounty would've been same as Ace's bounty, pre bounty inflation.
It's possible that we would see Enel return to the story, given the moon stuff hinted in the murals chapter. Dude had insane natural potential and talent. Mastered his DF, integrated haki to his DF powering his observation haki to one of the best in the verse, was able to instantly adapt to Luffy being immune to lightning and blunt attacks, etc.
All with only fodder to "train" with (or destroy) in the sky islands, with little to no opportunity for haki bloom, zenkai boosts etc. He had no reason to train his physicals, but somehow ended up with physical stats behind nobody except maybe Wyper in all of sky island.
If he returns, we may very well see him return as an admiral level top tier character. And it wouldn't even feel off, given how dominant and talented he was, plus his top tier DF, just give him advanced armament haki or something
