And yea, giving MW5 a bonus effect would make it a higher priority, that's what I was trying to suggest with the "Feedback" mechanism. Your suggestion is good too, but would prob be better to give the bonus only at 5 stacks and not before, to encourage using MW5 only when full and not hard cast anything. The only real problem I see with that though is a 50% chance to proc a free SS might be too powerful, that's probably 2 extra SS's in 30sec assuming we get about 4 MW5 procs in 30 sec. That may be too much of a buff and so something else would have to get nerfed, but I wouldn't mind that. For example.....nerf the damage of LB, but since MW5 gives us more SS it would even out and MW5 would still be top priority cause of the bonus effect, even if LB itself is lower damage.
Another alternative using the same idea, but taking some RNG out of it would be something like this: ""Each full MW5 consumed will give you a stack of "Storm Charge". Once you get 3 of these, your next LL (or SS) used will get it's cd reset. "" So every 3 MW5's used, your next LL can be used twice in a row for some nice burst.