Not sure if this has yet been stated, but it is pretty important I think it wouldn't hurt to restate it XD.
Software previews... or something like that. I know SMF releases beta's and RC's, but for certain projects, it requires more than that. Like TinyPortal (Though the creator of that is/was a SMF dev

) and SimplePortal which use SMF in many ways is a tough thing to do and can take lots of time for the developers to get it properly working with the new version. Developers might get their projects working with SMF beta's and RC's, but each time a new version is released, a lot has changed and then their product cannot be used by clients for awhile until they have it working with the new version.
Basically, these developers need to be able to see what and how SMF is changing before a version is released. I don't mean SMF tell them first, wait a week or more, then release it. But in some way allow third parties to have some kind of access to know more of what is changing in new versions of SMF in a day to day basis.
Basically what I am saying is kinda like what Microsoft and Apple do... When they are developing the next version of an operating system, they give developers access to SDK's earlier than others, sometimes even giving them the whole operating system so they can test on it and what not. It would be a lot for SMF to do, but you could have some kind of team to do something like that.
So yeah

Sorry if some things didn't make to much sense... I am sitting in a 90 degree room .-.