Definitely the basics:
1. Be able to define what is seen with the blog - such as date, time, comments.
2. Be able to determine how comments can be made - maybe a global variable that determines if there is public commenting or if the user has to be authenticated.
DataAssist could be used much in the way SecurityAssist has the registration solution. It would just require that the user created a database table with the necessary columns to capture what is needed for blogs.
Another way to do this - which I think would be a tremendous advantage to WebAssist - would be to make blog (and maybe later a forum) part of the Power CMS solution. The beauty of Power CMS is that it provides simple includes to easily place the dynamic content on any page. It then allows us designers to concentrate on look and feel of the front end rather than writing code all day long.
Just like the Power CMS includes already do, how great would it be if you wanted to add the Blog "Category" module to display categories and number of entries; anywhere you wanted on the site just by placing the include code automatically generated by Power CMS. The same thing for a "Tag" module. In fact it could all be broken out into modules that are PHP dynamic pages generated in Power CMS and the user would just place the desired include code to add those features.
That way, on a page that may not include blog entries, but you may want to display the categories or, say, latest comments, you would just grab that include code and put it where you want. But this would certainly be the most efficient way to do. As you know, I wrote my own blog app using WebAssist products but it is definitely time consuming writing the code to loop through comma delimited lists of categories or tags and then later creating the module where you first query for unique keywords and then query again for how many of each show up in the various blog entries.