Here's my thought, supercell are obviously not going to introduce this feature for "free" BUT:
I'd like to see it that while upgrading, heroes could be boosted for a short period of time, at higher gem expense to be used. say 10 gems for 10 minutes... If I had this option, I'd never miss a war again, or never revenge some dude without heroes again. This level would also help to work against the people that will try and "practice" war raids, in this way, its a short time you have to just get on with it!
Or / Additionally to this they could maybe make another boost for farming, say 50 - 75 gems for 2 hours. so if you have some time and want to run a barracks boost and do some farming, you can get your heroes back for a while, farm on, and then relax...
I know I'd pay for either boost, where I'd never gem hero upgrade time normally.



