Watt is the best for fighting Bowser; her regular attack does 5 damage, Goombario's does 3, Kooper's does 3, Parakarry's does 3, Bow's doesn't do any, Sushie's does 3, and Lakilester's does 3. I use Goombario when I just walk around, and since I'm level 28 and have the Bump Attack badge, I can just touch any other enemy and they will die.
"Sure, most Nintendo fans remain hopeful, because this is essentially a pre-requisite for being a Nintendo fan, but I personally have had enough. This company seems to hate its consumers. It doesn''t even know who the hell they are. We are not a bunch of idiot kids who want 10-hours in Miyamoto''s garden marvelling at how detailed the textures are on some giant tincan. We want ACTUAL VIDEOGAMES! Of course, Nintendo are too high on themselves to realize this."