I've been trying to figure out if there's a place in the 5e corebook that says, explicitly, characters can only make one attack per action phase (without a multiple attacks free action), and I can't find it. Does anyone know what page it's on?
Melee combat and all of the simple-action firing modes say they can't be combined with any other attack, but the complex action firing modes don't include that - why put it in for some and not others? Since the Rapid Draw adept power lets a character quick-draw and fire any weapon as a free action, it seems like it would stack with a lot of the other attack actions. Then there are martial arts moves like Throw Person that do damage but may or may not be attacks.
I know this seems a bit like silly min-maxing, but as a GM, I see a definite cool factor in a character who can get a foe in a clinch, throw him against the wall, then hurl a throwing knife into his prone body, all in one smooth combo action. And I've got some clever players who are probably going to be interested in the less-awesome applications, like a two-grenades-an-action-phase street sam.