If a state has a set of circumstances under which open carry would be deemed illegal, then seeing somebody open carry IS reasonable suspicion unfortunately. Of course I believe that shall not be infringed means exactly that.
Also, I don't get along with that "fits the description" crap. According to who? Unless a policeman sees it, for all they know, it's just one person SAYING something about another and not good enough to hassle a law-abiding citizen. If we say it is, then anybody can say anything about anybody else and get them hassled by police. In other words, use the police as an weapon against others. Of course I expect I'll have the minority opinion on this point. I cannot justify even minutely depleting the rights of everybody on the off chance it might catch one more criminal.