I’m attending a session about SQL Server Reporting Services 2008 where I’ve seen one of the mostly wanted missing features of previous versions of Reporting Services: it is the Rich TextBox component, that can embed placeholders to compose text with data producing reports for contracts and documentation.
The RDL still maintain a complete separation between text and data (and formatting!) so it is a nightmare to write by hand (but I don’t know anyone designing reports in RDL) but very good for a report designer to manage. Some more issue if you already have your own format for a “mail merge” text, because you have to parse your text and covert it into a more structured RDL, but it shouldn’t be so hard to do.