Using a builder to upgrade heroes really doesn't make a lot sense.
I have been kind of disturbed by how builders "upgrade" the heroes or rather the animation at least. If the heroes became heroes after over consumption of Dark elixir (which could be a euphemism for dark ale or other darkly coloured alcoholic beverage).
Then wouldn't the following animation be a bit more appropriate:
- Hero sits on a throne on their altar drinking copious amounts of Dark elixir, served by the builder
- Hero is passed out next to a flagon of dark elixir, while the builder tries to wake them up, Hero wakes up every hour to take another swig of dark elixir before passing out again and the builder goes back to the trying to wake them up animation
Or maybe something to do with training or actually strengthening:
- Builder dons on a coaches uniform while the heroes go on a "Rocky Montage"