*shrug* I don't think the cannon
is oversize (and Mania King's doesn't look that much smaller, judging by photos). Or a problem in robot mode. Not perfect, certainly, but not an outright problem. All it needs to be perfect is some sort of clip or harness to attach to the side of the arm instead of on top (and preferably to the forearm). The size isn't the issue, the mounting point is.
The Headmaster gimmick doesn't hurt him, IMO, although sacrificing some paint on the tread pods to paint the exposed surfaces of Nucleon purple would have been a good call (one that the Legends version missed, I might add
). The implementation of the mask is spotty, but the gap part doesn't look that bad to me in-hand.
As for "better off without the third mode"? The only difference that would make is he'd be minus a couple of pegs and the cannons sculpted inside the paldrons
I think the starfighter mode looks a less dorky than the '86 Galvatron's third mode, which is a rather chunky raygun.
I personally think Titans Return
was the line for Galvatron - and Hot Rod, Wheelie, Kup, Blurr, Scourge, and Arcee - simply because of the timing.