EASY WINDWALL TWEAK!!
rough idea of new mechanic idea:
- windwall slows projectiles by 99% for ~1 second. any projectile passed trough will cause 40-80-160-240-480 less damage. (down to zero)
think about that for a while. 
rough idea of new mechanic idea:
think about that for a while. 
Nope. Just have him spend flow to use windwall.
Sounds like a heluva lotta work to make a skill interaction less clear for those seeing it.
Or:
fix size of wall (live rank 2 or 3) no longer grows with rank.
spawns at auto attack range. Adjust drift difference to keep it around the same overall spot.
duration scales with level. 1 to 2 seconds based on rank.
Ez