Definitely will echo this. The app I work on is probably a lot of bloat which the op is complaining about but compared to the last app I worked on it's quite a bit less and compiles at least 5 times more slowly due to using swift where as the last project was 100% obj-c. Even if we could somehow manage to convince management to let us clean up the app we'd still be at the mercy of however long the swift compiler takes.
Don't use type inference, and modularize the codebase into separate static libraries. That should reduce the amount of full rebuilds, and should make builds faster. (ETA: also try to avoid generics.)
Ofc, probably a lot harder to go back and redo a huge legacy codebase where you still have new deadlines to meet, but for folks just starting out, these should be guiding principles in a Swift codebase if you care about compilation time.
