Use regen in my car and my trike. Don't give it a second thought. I'm guessing wheel size would affect peek amps. Get top speed, small wheel, small battery and hitting max regen could cause issues for a few seconds.
People who use it all the time know not to have a fully charged battery. This goes for my car as well as my trike. I don't have any hills or mountains that would max my regen out or where I could not hold back my trike's speed and not slow down. Do have a larger battery than some and a 26" wheel.
My brake pads are 3yrs old and have no plans on changing them in the years to come. Chalo's point about drop out is correct you need to clamp down the axel and expect more torque from regen. I have my regen come on soft as not to jerk my axel in the opposite direction and have my TQ arms pulling in opposing directions. Need to go to clamps.
No over charging or Amp peaks. Used to read BillVon mountain adventure's where he would over heat his motors with regen.