New Tower + Unit or Spell

Hello,

i was thinking to Starcraft and this idea comes to my mind:

A lot of ppl want a invisible spell.
Why don't give us this spell or better a flying unit which can cloak all Units in a area to improve some strategies?

When this unit will exist, then we need for defense a new Tower (or give anti air this ability) like a "detector" which can spot this Units in a area.

This would be sooo interesting, when a Player use this spell/unit and on the ground are some epic Combos attacking walls/buildings.

Also maybe valkyres could make a lot of AOE dmg whit this combination???

What do you think? :D