As someone who's responsible for migrating the users of a large breaking change (~300 projects), it does discourage you from making a breaking change. I'm not c

As someone who's responsible for migrating the users of a large breaking change (~300 projects), it does discourage you from making a breaking change. I'm not convinced that this is a bad thing though. Breaking changes can be both expensive and tempting. By making the author of such a change feel the cost of it you prevent the migration work from becoming an externality. It also encourages writing tools for automating this stuff. A big part of the motivation for polyup (https://github.com/PolymerLabs/polyup https://github.com/PolymerLabs/polyup) was the fact that we'd be responsible for getting people to upgrade.