I like this idea a lot.
I would just change that, while moving your AP don't regenerate, when started walking the AP you had is cut to half, when started running, it is cut to 0...
This would make many tactical opportunities, not like now where it is still best to run all the time, and walk is good just for the looks.
About speed of AP regeneration, it should vary according to your total AP amount, but not as much as now.
It would need careful balancing so that 12 AP BRoF guy with P90 just doesn't pwn all...
Haraldx: the BGers would then have to wait few seconds too to burst you then, when they come in front of you.
Anyway it shuldn't be 7 seconds, but like 2 max.