Thanks for your feedback!
As Mike mentioned, we are working on better domain support. A HB migrator is also planned, but migrators are very time consuming to build and most people are migrating to us from the other guys. Hopefully we'll be able to focus on a migrator once some of the bigger issues (like the domain plugin) are resolved.
You should definitely be able to write the other extensions you need, or hire someone to do it if we don't have support for them. Blesta is more developer friendly than any of the other guys, and more and more developers are becoming familiar with Blesta.