i know there has been a subject on this and most people are happy to use the old deathing rules etc, but i have come up with some easier to play ideas that dont rely on plussing and minusing d6 rolls.

power armoured marines. 5 action points, can do a 180 turn for action points and move sideways for 1. (this is for manouverability)

fights with 1d6 in close combat, but may not guard. loses draws. (this shows their weaker armour).

weapons

bolt pistol. as bolter, no overwatch. May use guard.

boltgun. As storm bolter but only using 1 dice.

flamer. As heavy flamer but only has 3 shots.

Plasma Gun. As storm bolter but uses 3 dice. roll of a triple gun explodes killing the bearer.

melta gun. Range 12 kills on a 2+, can only be fired once per turn.

heavy bolter. As assault cannon but only using 2 dice. same ammo, no explosions though.

missile launcher. As heavy flamer but kills on a 5+. unlimited ammo, can fire once per turn.

I know some of the weapons are a bit sketchy but the idea of just reducing the bolter dice and removing guard instantly makes power armoured marines weaker but not too weak.