There's at least one good reason to leave it the way it is for a time: keeping the block creating nodes (i.e. miners) on standard code (file under "critical piece of code which a lot of money is tied up in"). Long term stability is important to this system, and the passage of time will do alot to make sure that different miners on different implementations can happily contribute blocks to the same chain. The better that all developers comprehend the system, both for the reference client and any re-implementation, the less likely we are to deal with the mild cataclysm of system-wide block rollbacks. If that means monopolising block creating for a while, then it's possibly not such a bad thing. I'd prefer that it weren't like this, but we have highly capable people working from both sides of the gulf, I've no doubt that the situation is as good as can be reasonably expected (for now).