Exactly. It actually seems to go the way that various other PHP frameworks can be replaced with Symfony2.

There is already a compatibility bundle for running Zend Framework apps with Symfony2:

http://symfony2bundles.org/beberlei/WhitewashingZFMvcCompatB...

And I'm working on another bundle that allows running Midgard MVC apps:

https://github.com/bergie/MidgardMvcCompatBundle

Whoa, this is very cool. (I have a legacy Midgard MVC app I'd like to get rid of.)

Between Symfony2 and Silex, I'm not sure what case there is to use anything else anymore. It seems like the low and high ends are very well covered in the Sensio Labs environment, and I'm not sure how much room there is in the middle.

Ping me on Freenode #midgard and I can give you more info how to proceed. Out of curiosity, though: are you sure this is Midgard MVC and not MidCOM, the older MVC framework for Midgard?

Doesn't matter, though. We're building compatibility bundles for both. Though Midgard MVC is already in somewhat running state.