Yes, but they are not show stoppers for everyday use of the N900. Besides, you can always install MeeGo on it, even though it is premature for everyday use right now, but some day... You cannot do this with any other commercial device. The N900 is very special, and only, and I repeat - ONLY - Nokia has been so kind as to make such a device available to the public. So crying about stale Maemo development is really way out of line IMO. Maemo works just fine, it is stable as a rock when used in a normal way.

Anyway, Nokia is like God. History has shown they both operate in unpredictable ways, so you may still get an update or two of Maemo as well.