We all love heavy attacking for resources (no we don't) but it seemed like zos wanted to make heavy attacking more viable against off balanced targets, therefore the suggestion, instead of double resources gain when target is off balanced, make it X2.5. Still damage loss, still worse than spell symmetry, but definitely more viable.
While at it:
Fix lightning staves getting X4 bonus from vMA staff.
Make vMA staff giving heavy attacks triple the dmg boost (to better compare damage gain on la vs ha compared to time taken to use).
Rework fire & ice animation + sound to feel more fun.