Pausing of upgrade of non defensive buildings and heroes

Hi Guys many extreme clasher's support that heroes should be available during upgrade and i too suppurt this but today i came up with a new bright Idea.

I think we should be able to pause upgrade of non defensive buildings like ( barracks,spell factory DB,D spell factory etc. ) and also upgrade of heroes and then resume it any-time time either free of cost or it should charge 5% at first resume than 10%cost at second resume than 20% cost at second resume and so on. I'm not too confirmed that the resuming cost is convenient it is upto devlopers.
By this feature we would be able to use heroes during the war by pausing there upgrade and we will also be able to use spell factory and dark spell factory.

Plz feel free to give your opinions or correction thanks