thanks for this one - defo going to give it a try, perhaps this evening if i have time.
The Heavy is hugely inaccurate, especially as they level up (other classes improve at a far faster rate). Try and get your heavy on higher ground, or closer, and treat them as explosives experts who've been given a gun rather than soldiers.
Archangel armour on a heavy is a bit cheeky as well - stick them up above everyone and the height advantage (plus 20 aim) will regularly see you getting 70-80% chance to hit. Plus there are far fewer impediments to rocket attacks...