I'm not sure he's amazing... thanks to the ol' tether buffs of P:M he's not horrendously gimpable, even with the nerf to his PK Thunder 2's recovery range, but I can only imagine bein' off-stage while playin' Lucas as bein' rather scary. Havin' a very punishable grab and what I wouldn't call a terrific ground game don't help neither.
'Course, I wasn't a Lucas player in vBrawl neither. Haven't even played Ness in any Smash game. Add in the fact my only experience with P:M Lucas is 20 minutes of fightin' CPUs, my opinion is very much likely t' be full of shit.
Far too early in the metagame t' say. P:M strives to obtain a competitive balance like no other, but that don't mean they've achieved it just yet.
I personally dislike how they changed Mr G&W and Snake, but concerning tier... I'm pretty sure Lucario will be one of the highest and yes P:M is real even