* Javascript -- I hate the language, it has enough warts to make it unpalatable
* Dart -- I can see it, that would be great, still kind of new though
* Python -- I understand they could have done it, but it was a political decision not to (at least according to Guido's remark during one of the PyCon's), performance might not be up to par on some devices
* Go -- too low level perhaps, but it would be cool
And "better or just acceptable" is rather dismissive of the facts.
Assuming that Google had done these, there should be no reason that Python would not be fast or robust enough.
Low entry thresholds for developers is nothing but poison for a platform.
This was probably very desirable to Google in 2005 as it gave them the chance to court mobile manufacturers with the promise that their operating system can be deployed across a range of devices and theoretically all apps etc should remain functional, regardless of hardware as it's the VM that's the deployment target, not the phone.
Remember that back in those days the mobile OS world was god awful, Symbian was abysmal, JavaME was broken and Windows CE....well let's not go there.
It seems odd to me to design a platform that only supports one programming language. What happens when people find better ways of expressing their intent?