How wonderful!
I wish you the very best of luck; altho I think you may have set yourself an impossible task here. Like many of us, I am an ex-psion user, and have never found the old agenda bettered. Probably like yourself, I always start with a week view, to see things in context.
Now I use
Oyajin(as many people know, I'm often raving about it here
). It does these things well:
1. Works on arm and mips, as well as PC
2. Database on CF card not memory, so can use without sync
3. Dynamic screen resizing to fit all resolutions
4. Ability to set repeating, overlapping, continuous appoinments, change colours, set alarms, etc
5. Ability to schedule items in combinations of different views - Month, Week, Date, to do, etc
What it doesn't do - and I think a PIM app should do - is allow the tagging of appointments by category, or etc, so you can filter by "project one" "family" etc.
If you are into GTD you might find
this site useful, altho they are a bit mad for it.
Good luck!