Are there any? Other than heavy attack weapons like gunblades and glaives

What weapon types are good for them? I already know gunblades do insane damage, but they feel more like shotguns than melee; and I've already modded a Machete Wraith that supprisingly still kills even steel path grineer, but it lacks the crowd clear aoe I wanted. Any ideas?

Is there anywhere I can check to see where an enemy's "head" is? I'm having a hard time figuring out where the archon's or an amalgam demolyst's headshot zone is.

Wisp P should be here soon, does that make Gauss the next prime? I was thinking of using him as one of my mains, do you guys think its worth waiting for it till september-october or to just go for it now?