Yeah, I was aware of the Royal Guard, the only issue is... well, usually you get directed by a Darth (Baras, Zash, Zhorrid/Jadus, Tormen, etc.). The Royal Guard are directed specifically by the Emperor . . . I just don't really know if that would work. I mean the class idea is solid, but the implications are what's getting me here . . .
As soon as you said riot guard I was thinking this
also, the idea of a scattergun using true melee character wading in with pepper spray and shield bashing sounds really cool, but I think without a 'proper' melee weapon people would assume this is a vanguard/pyrotech copy.
Also as to the imperial guard idea and being directed by the Emperor, maybe that could be part of the story? You start off as a rookie, and then attract the eyes of someone 'very important' (having no clue who they are.) It would be pretty BA if I played a melee royal guardsman who's final/very late (start of act 3?) class quests involved finding out who he had been serving all this time, then stemming from there. I suppose however that a royal guard would be less military and more secrecy, but I guess Bioware would have to integrate the two somehow. Being a military leader who even the sith bow to is, again, pretty BA.