I checked icalendar on Wikipedia, and that certainly could be a good thing.
Personally, I want something in my pocket, independant of i-net connection.

I have looked around a bit on the PIMs mentioned in the Wiki, and e.g. gpe calendar seems to be going in the right direction.
As to "not good enough", as (un-) far as I have looked, I agree with you.

To me, the advantage of Nokias Symbian PIM (that I use) and Palm (as far as I can see) is the INTEGRATION of the different apps.

Of course, as Linux ( Nokia, Mer, Openmoko, etc.) probably overtakes other systems, good PIMs will be developed.

And Symbian will, of course, not end with a bang but with a wimper, or possibly vanish quite slowly and end with a grin like the Cheshire cat.