Almost all spells in Starcraft are damage *over a period of time* Why not just change the anti-armor missile to be shrapnel that does damage over time to fit that motif? 2 different debuffs or something:
Damage (30 over 3 seconds)
Armor reduction (lasts 10-15 seconds)
Would still allow the missile spam to go ham (unless a unit can only be affected by 1 debuff in which case the 30 damage might aswell not exsist.) personally i think a movement speed reduction with a lategame buff would be the better solution.
