Well, unless it's been retconned like everything else in Superman's continuity, Lex technically has physical perfection, which was granted to him by Neron after his clone body became infected with a special clone disease that started hyper-aging him. I thought that Nightwing's line in Public Enemies, "go to hell," and Lex's response "I've been. It's overrated" was a nod to Lex's deal with Neron and the reasoning behind him so easily beating Nightwing (aside from the nerve gas, I mean).
That physical status, combined with armed and unarmed combat training from both Hope and Mercy, means that Lex is about the furthest thing from being anything close to a pushover in a fight, whether he has his now-clichéd battlesuit or not.
Sadly, this does seem to have been forgotten, judging by Lex's portrayal in "Up, Up, and Away!" (seriously, he really should've easily kicked powerless Superman's ass in that final fistfight). I just hope it was only forgotten for the time being, and not completely retconned by Superboy Prime.
Dear DC Comics, as much as you try to forget it (God only knows why), Superman
did actually have a set continuity of stories during the 90's (so very hard to believe, I know). Use them to your advantage, for God sakes.