We should be able to use more than one builder at a time on the same building, to speed it up. For example, if I used all 4 builders on a Town Hall upgrade, it would take 1/4 of the full building time.
Once you get to higher levels, it's practically useless to have more than 1 or 2 builders because it takes a while to save elixir and gold, then the updates are so slow. Allowing multiple builders on each item would alleviate some of this.
