pocketmine in python

All jokes aside, plugins in a separate language is indeed feasible:
- If those languages have C interopability, just a PHP extension would be sufficient to interop with them flawlessly
- If C interopability is hard (PHP extensions aren't that easy to write indeed, and interop in some languages are also hard indeed) or not possible, it is possible for PocketMine to start each plugin/language as a child process and communicate events and actions through stdio or otherwise some local communication sockets.

Both of these can be achieved through plugins. However the latter tends to be slow, and is best done asynchronously. It has been a whole year since the initial async events proposal, but BlameShoghi that it's still hard to implement.