Hi There
 I would say it depends on who you are playing against. That is a lot of models on the board. If you are fighting against only troops then it could be fun. If you are fighting against vehicles, Then I would switch out the grenade launchers to meltas in the infantry squads.
 
 That's a lot of dice to roll when you get in range. However if you are playing against Tau, then they will more then likely pick you off because you get in firing range with the majority of your units. 
 
 I played one of your platoons against a Tau and was destory'ed. Then I played against a Necron and was doing decent because of my rolls, but in the end failed.
 
 Good Luck, It should always be Fun, it is a game.