New Option Request: Upgrade Heroes in the Lab

As an avid clan war participant, I've long wanted to use heroes while they are upgrading. I understand, of course, that there are substantial logistical issues with allowing that (allowing heroes to be used during war but not for normal attacks), to say nothing of the potential gem hit SC would take if people weren't goaded by their clan mates to gem a hero upgrade for their clan war attacks.

The SC reason against allowing upgrading heroes during attacks has always seemed more technical/logistical than financial, though.

So what if there were an alternate way to upgrade heroes? How about in the lab?! You could always upgrade the current way if you wanted, and there would need to be a minor safeguard so that you couldn't upgrade a single hero in both the lab and the traditional way, but that's about it.

Pros to upgrading heroes in labs:
- Allows for hero usage during clan wars (!!!)
- allows people who are done with lab upgrades for that TH level to continue using their lab for something
- more options -- lets people choose between upgrading heroes or other upgrades
- everything else can be upgraded there (normal troops, DE troops, spells -- why not the ULTIMATE troops?)

Cons to allowing upgrading heroes in lab:
- ???

what do you think?