heroes can be used at war while upgrading idea

that is wake uping them in the middle of upgrade by using gems or summoning them in the middle of upgrade by using gems
i know a lot of players have a thinking that geming in clash of clans is just a such thing of disgusting even at geming on heroes and other project. and this is just how to enjoy the game all the way of time
if there is a plan that supercell already owe at heroes in the next update i'll on the side of supporting them.
then if there arn't. then SC looking for more reasonable update on heroes that is summoning them like other troops in the middle of upgrade by using around 2-5% dark elixir off current level upgrade cost and current time regeneration. i know a lot of players very need them to using them for something while upgrading. and i know too some of player spending their progress time in coc just for upgrading heroes if elixir more thatn enough for that
but i thing SC need to suggest them to toggle them into the sleep mode before upgrading if they don't wanna using them for a defense
csdf
-regardbar