This reminds me a lot of Swift's early days. Build times, dev stability, learning curve, static analysis (remember the esoteric compile/lint errors...) even rev

This reminds me a lot of Swift's early days. Build times, dev stability, learning curve, static analysis (remember the esoteric compile/lint errors...) even reversibility (i.e. Apple had a tool to convert from Obj-C to Swift but not the reverse) were issues that were brought up. If Kotlin hopefully follows Swift's path then these will get ironed out over time.