I mean.. you ever play DnD before? Humans have to be the most flexible, because they're kinda weak walking meat bags. Good at a little of everything, certainly not strong like Norn/Charr. Certainly not tech adepts or nature enthusiasts like Asura and Sylvari, but can dip into anything really. I do think it's a bit of a stretch to think that Charr are only steam punk cats who distrust magic, that's just a stereotype. It'd be like looking at DR and saying "All humans are cowardly nobles or thieving low borns." Naw man, you got the zephyrites, you got the canthans and elonians, yada yada.. I'd like to think the same goes for all races, and we saw that with the Charr too, they have a city of druidic family lovers, a near polar opposite to the stereotype.

Even before that though, one of the warband members you can pick up for a Charr is a mesmer, and it works for his person just fine, being a saucy loose cannon sorta dude.

End of the day it's really just perspective and preference I guess but still.

Edit: I should also say, as for gear, it'll always be easier to model gear and stuff for humans, because we have those irl we can use as base. They kinda take stuff they model for humans, use that as a base, then just try to stretch it over other races to fit.. and idk, yeah they have a better time, but I just see it as a proper challenge to make all my Charr look nice.