We pour a lot of time and elixir into our labs to level them up before we even start on the troop upgrades for that level. It'd be nice if by upgrading the lab, at a certain level you opened an extra slot that allowed you to upgrade more than one troop at once. It could be capped so that, say, at lab level 4 you unlock one extra slot and that's it. Perhaps it would allow one DE troop and one regular elixir troop to upgrade at the same time. Or one troop and one spell upgrade.
Right now I'm levelling up my hogs. Went straight from completing level 2 upgrade to level 3 upgrade. That's 18 days straight of hog upgrading while my elixir is racking up. I'm planning to go straight to level 4 after that so I'm guessing I'm looking at the best part of a month on just upgrading hogs. Be nice to run a normal elixir troop upgrade concurrently.

