Well, the "team" never actually carried guns. Wes carried one and sometimes two handguns, Colt 1911 .45's or one of their clones, I believe, and occasionally a Remington pump shotgun. To the best of my knowledge, he only started carrying them, and his folding sleeve blade, after he split with Angel over Connor's abduction. Other than that, the only use of gun against demons on the show was when Gunn's old gang used them in one episode.
As for myself, I have no problem whatsoever with the use of guns whenever they might be effective. That doesn't mean that I wanted the show to turn into the Buffyverse version of "Blade" or "Underworld", but the use of more modern weapons in the Buffyverse would have made perfect sense. In fact, I've always wondered why, other than possibly the usual liberal anti-gun views of the Hollywood community in general (sorry, folks, just the conservative, Southern gun owner's attitude in me rearing its head up here) neither show ever modernized their armament, especially the assorted non-super powered members. It would have only made sense, especially in view of how well the rocket launcher worked in Season 2 of Buffy, to have, occasionally resorted to something besides the museum pieces used on the two shows. That's one thing that made the Hunters on "Supernatural" much more logical than the Slayers and assorted demon fighters on "Buffy" and "Angel."