Hi Larry,
Although I don't plan to use Rico, I am coding with a view to allowing the code to be as "happy playing with others" as possible. So nothing "should" prevent you linking in Rico3 if you like.
The main reason for the switch is the level of documentation, and number of "plugins" which are available for jQuery. It was a toss-up between a Prototype-Rico-Scriptalicious approach or a jQuery-jQueryUI approach. Frankly either set would be ok, but jQuery seems to be documented, and has more community support.
There are some other "under the hood" changes, but these probably won't affect you overmuch. I'm trying to make sure that NT4 apps are as compatible with NT5 as is possible - obviously there easier it is for people to upgrade the more likely the upgrade will be done.
I know we've discussed the record-id being in the form before, and that's something I've changed.
Cheers
Bruce