Robot suit Lex never bothered me. It's not like he busts it out in every story and it makes perfect sense in the situations where he does use it (like the recent Forever Evil arc).
I also never bought into "peak physical condition" Luthor. Lex, to me, seems like the kind of guy who would be in shape and healthy, but never give so much time to it that he'd have the "alpha male" look. He'd work out because he recognizes the advantages physical conditioning give to mental health, but wouldn't necessarily enjoy it.
I can only speak for me, but while I didn't care at all for that stuff in MoS, I don't actually want to see Superman spending an hour angsting about killing Zod or failing to save people in Metropolis. Just acknowledge it as much as you have to and move on.
That's where I'm at. I do hope they address it, but it seems some people want that to be movie's entire narrative and I don't get that. Comes across more as wanting vindication for the complaints as opposed to wanting a good story.