Well, i do like the directional shouts mentioned and CutterJohn's idea is great. My ideas are more built around the old system:
A full "Incomming" sub-set: Incomming Max Unit, Incomming BFR, Incomming Magrider, etc.
So for instance, V-I-V-T could be the shortcut for Incomming Magrider. (V = Main macro window, I = Incomming, V = Vanu, T = Tank)
Or perhaps instead of "T" use "M" for Magrider. This might be better because of all the different vehicles.
Also, Jpsousa4 posted a thread about this on planetside.com forums a while back:
Voice Macros in PS2