Gunnery is good i agree but train a mw in tactics and build a 3 assault 1 heavy unit. Heavy mech should be built for speed not accuracy must have jjets. Build it for melee. Put your tactics mw pilot. Max armour Max jjets and equip mods that are compatible with melee and movement. Evasion is not so good with the update but if you can act before the other team you can destroy the enemies heavy + assault units quickly. Also by acting earlier you can reserve to see what the other units are going to do (position) or reverse if you are tanking your heavy mech then you can draw fire from enemies. I would only do this if you have 1 or 2 long range ac equipped assault mechs. When (not if) you achieve stagger on an enemy assault mech send in your heavy for finish or critical. A Mechs should be built for damage output at all ranges. With gunnery pilots they can easily disabled / stagger enemies. Let your highly mobile heavy mech destroy vehicles.