- chain jobs - needed for larger projects; ideally this should even allow composing jobs to have nice, modular jobs which can be launched standalone or chained

- some kind of powerful templating system - needed for reducing configuration duplication; ideally this would keep track of all the "children" in case of updates

- you also probably need enterprisey features later on, like SSO using AD/LDAP, fine grained ACLs based on groups, etc

But job chaining and job templating should be higher priorities for the workflows since they affect the overall architecture. Jenkins has been struggling for a while to re-architect to allow this, not entirely successfully.

You also want a plugin system if you don't have one, especially one with dependencies (i.e. the Git plugin can server as a dependency for the Github plugin).

My 2 € cents :)