So here's my idea to make the builder more better.
I think it would be nice if you could boost a builder. Maybe boost their speed to build and make it 2 or 3 times faster by 10 or 5 gems. I think this would help a lot, for example you'll upgrade your storage and it takes 1 day, of course the resource you used to upgrade that building would cost you a lot, so you have 1 day to attack and gain your resources back for 1 day (which is the time required to finish your elixir storage upgrade for example) and have enough resources to upgrade again once the elixir storage upgrade is done, but what if you have more than enough resources? The loot you get from attacks just get wasted since the upgrade isn't done yet and maybe you don't have other builders since the builders is really expensive since it needs gems. So yeah this builder boost would be awesome.
Or atleast you could make them "upgradable" in which we could upgrade our builders.
Gem box
Alright atleast make it 30 gems per gem box or maybe make it more often to show up on our base. You know when players get high leveled, the achievements isn't really easy. Yeah there are easy ones and what? You get like 10 to 5 or 15 gems, thank you for that but that's not helping when you need a 2000 worth of gems builder, or 1000 gems for a builder. So yeah I suggest this.