I would phrase some of your points more strongly. Furthermore, shall we include a roadmap for the functionality of packages as well? I ask because it makes a lot of sense to go beyond the needs of .LRN with regards to roadmaps for packages. Furthermore, one strength of the toolkit is the large number of pre integrated packages.
The following suggestions are only for 5.3, as 5.2 is already frozen and should focus on bug fixing due to the magnitude of changes seen in the code.
I'd set one goal to make OpenACS Core XHTML compliant and switch the header to XHTML Transitional. This move should go hand in hand with a .LRN cleanup of the HTML code in the packages used by .LRN to make them XHTML compliant.
To make the site easier to manipulate with a CSS, I suggest to wrap every HTML code generated by an < include> with a CSS < div> tag. The ID of the < div> tag should be automatically generated from the package_key.lib_file_name combination with the possibility to override. This should make the integration of code pieces in the CMS parts of OpenACS easy, as you can define the look of these pieces more easily.
For testing, it would be good if we would support a framework that let's anyone write a test by going to a website, clicking around and enter data, thereby generating a storyboard for the testing script to use. There are mechanisms for this out there and Eduardo has proposed some already. This should enable everyone to easily generate test cases once a feature is developed, making sure that no changes break the current system. This should enrich TCL Webtest, which to my knowledge is useful in defining test cases in advance to writing the code, thereby following the ideas of agile development.
The form definition and widget changes proposed by Dave should be based on the ideas you can encounter in Contacts, Assessment and Package-Builder. No need to reinvent the wheel....
As for windows support, due to the fact that AOLserver runs on Windows and both supported databases run there as well, I think we are already there (Windows support I mean). Still I would not recommend it :).
Another topic would be HTMLarea. We should move to the latest working version (Andrew did some tests with the CVS version I think) and maybe support FCKeditor (http://www.fckeditor.net/) which looks nice as well and does not break Safari (it does not support it either, but at least you can add/edit the text). From the activeness of the community I'd focus though only on HTMLarea.
Also I'd suggest to dump spellcheck in OpenACS and enable it in HTMLarea. Or at least turn it off by default. It has been causing a lot of troubles which is one of the reasons most 2.1 sites have turned it off now.
Furthermore, I'd like to collect feedback from people on ad_form and what is annoying in it's code and useage so we can further finetune this centerpiece of OpenACS.
But the main goal for 5.2 should be to fix all outstanding bugs in OpenACS core and collect the suggestions together as a TIP for changes in 5.3. And I'm not talking about only release critical bugs this time :).