We should first decide how powerful we want the syntax files. If it's power we want, XML just won't hack it. It would be way to complicated to create something as powerful as the things we have discussed. Also, a poll is a bad way of deciding important things like this. It should be reched through a series of discussions about what we really want and where we want to go.
For more information about what is being discussed at the moment, please read this thread
. It contains the early stages of the specs I propose we use and it also has some talk about what we want to do with a syntax definition.