Boost on Mines and Collectors to improve loot

Hello,

Don't know if someone already suggested this, but I see a lot of complaints about the loot as from a certain level, and have the impression this is partly due to the fact lots of high level still have quite low level gold mines and elixir collector.

Why not have a temporary 1 gemme boost on upgrading gold mines and elixir collectors ? I'm pretty sure that would have a very positive impact on loot on the long term if all higher level were to upgrade all their mines and collectors to lvl 11.