Eventually a crippled version of the new software, so-called "community developed", will make it to the N8x0, but it will only work to the extent that it will make you crave for the new device.
don't pay attention to the buzzwords and the fanboi spinning and consider this: "Knowing what I know about how they've done things re the tablets since 2005, are they still worthy of my cash?"
And please, don't make the mistake of assuming Nokia is interested in or furthering the open source community, because they aren't. Or, to be more precise, they're only interested in a community that brings them profit.
In view of this, IMO the only mistake Nokia has made is in putting the launch date of the new tablet so far ahead (summer '09, which most likely will translate in to Q409) and already starting the covert "no more bugfixes" operation.