Behatted Wanderer: I had that experience in a lot of my early philosophy classes (particularly applied ethics - I'm still wary of any formal debate on abortion), but I've been studying philosophy in debate-led settings for six years now, and the trend has been steady improvement.
Also take into consideration that the Escapist's forum users tend to be intelligent, civil, rational people. Opinionated, sure, but most of the debates I've participated in on here have gone off mostly without devolving into yelling matches, and people who are repeatedly obnoxious do tend to get banned etc. I think a philosophy group could work quite well, and I'm definitely in if one appears.
That said, a couple of rules that I think should be included; 1> let's have strictness with spelling and grammar 2> no attempting to convert anyone to atheism or any religion (not because I think it's necessarily an unhealthy debate, I just don't think it's possible to convert people by argument, and it's only going to ruffle a lot of feathers the wrong way).