Whether it's full MeeGo or not on N900, the biggest issue now (in my mind) is the complete change of package management system.

If MeeGo had never happened and the N900 stayed on M5 but remained API and package manager compatible with future Maemo releases, it wouldn't be so bad - the N900 would continue to get most apps, and developers would only need to support one DEB package management system (or two, including Symbian).

Now with MeeGo, apps will be distributed as RPMs. Not all apps will be developed for Nokia devices as developers may be targeting x86 netbooks running MeeGo, but their apps could be packaged for ARM/MeeGo as an RPM, and they might do it as it's largely a no brainer (in theory) and massively increases their market for next to nothing.

But continued DEB support, particularly from developers not principally targeting Nokia devices? Forget it, it's a dead market so best to let it die than keep it on life support.

RPM support for the N900 is essential, one way or another.