In my experience theres not manny who want to be a heavy trooper (heavy as in MAX). The slowness turns people away, esp when you consider that you can do much more in a reinfroced armor, use vehicles and carry more than 1 wep. But me personally i've always loved beeing the trooper whit the biggest gun
Forgott to mention that MAX's also can't use anny tools or things you can carry in your inventory. Might be able to use nades tho, not sure bout that.. Maybee Hamma could enlighten us? =)