I never found the foreguard pistol grip obstruct magazine change. I never saw the version which had the side folding butt, I am familiar with the AK type folding butt version.2. It had lots or other problems like the front pistol grip which interferred with a quick change of magazine, the side folding butt which was not comfortable in carriage, etc etc. But the main problem was the incompatability of the ammunition.
The how come the M4 carbine does not face the same problem? It fires the same NATO SS109 5.56 mm round that is used in the INSAS.4. No, it is not hard to design a muzzle compensator, but how would that eliminate the sound and flash. Agreed, AK fires a high powered round too, but its 7.62x39mm amn had the mv of approx 700 m/s, which is why AK was so effective in close range, burst firing mode.
To correct you, we hate the Sterling L2A3 that and not the class of 9mm carbines. It fires from the open bolt and is unsafe, as you are aware. The 2B with the double sear tried to address the issue, but we have hade enough of the Sterling. It is better if it is issued for VIP protection of corrupt politions, its unsafe nature will rid us of a few scumbags in khadi.5. All of us want to get rid of 9mm carbine, but there is no viable alternative yet. Let's see if DRDO spins some magic
If the 5.56 mm carbine is a problem the give us a 9mm gas operated scaled down version of the INSAS. We will be forever grateful.