We always wondered whos bright idea it was to take that out of the lineup, especially since about 1/3 of the historical battles and scenarios in our training manuals from WWII, Korea and Vietnam involved the use of canister fire to keep infantry off tanks. MGs are nice, but when you're buttoned up and trying to look through slits to aim and fire, its kind of difficult. Not to mention its not really effective when you're being swarmed.
Canister opens up a nice hole in the determined attackers, and can put a real "RUN AWAY" incentive to the less determined ones.