Burst is a big POS, in my opinion.
We had no problem firing short bursts from our M16A1s when needed, it doesn't take a rocket scientist to fire a burst from full auto mode.
With a clip-on bipod, you could do a reasonable amount of auto if needed in a pinch, for an FPL of fire for example, if your squad belt fed weapon was down, or more were needed.
With the M16A2 "Burst" mode sometimes you would get 3 rounds, sometime 2. I found it a bit ridiculous.
The Army needd to go back to safe-semi-auto, or do like the Germans and do safe-semi-burst-auto.
Either that or go back to semi only. Burst is useless in my opinion.
But then I am a heretic anyway because I thought that with the exception of the heavier barrel and 1-7 ratio, square FSP, and improved furniture, the M16A1 was better than the A2 in all other respects. The sights were more suited to combat, the stock length was better and the firing modes were common sense.
Call me Old School.