I watched Powerbang's video today and just from gleaning some posts, Supercell will never allow upgrading heroes to be used in war. PB stated it is probably because gems are huge source of cash flow and they wan't people to spend money on gems etc.

So instead of making another post begging for this, how about this idea:

Supercell allows for a boost to collectors. Why shouldn't supercell have a gem boost for either buildings or upgrading heroes. The feature could be spend 100 gems or 500 gems and the boost would cut down building time or upgrading time by half.

THINK SUPERCELL, THINK OF ALL THE MONEY PEOPLE WOULD SPEND ON THIS.