I just ran through a quick walkthrough of Roo after hearing about it at Rod's talk yesterday on the Hyperic acquisition. Roo seems very compelling and can't wait to see what turns out for the GA release.
Here are some quick thoughts:
1. I hope that Roo will consider using a templating technology like Facelets for JSF or Sitemesh in Grails to create/compose pages. I really don't want to go back to the old way of coding JSPs. To that end, I hope you can choose your Web framework (JSF, Struts2, Spring MVC, etc.), like AppFuse, to leverage your staff's particular expertise to extend what Roo starts.
2. I hope there will be SWF integration which will provide OTS support for workflow and Web 2.0 capabilities using Ajax4JSF. Also, the same with Spring Security and Integration.
3. I wonder how easy it will be to maintain several .aj files per entity. When I first created my entities I was surprised by the number of aspects and I'm not sure if that would be too foreboding to the uninitiated. Nonetheless, I really like the approach to that end, instead of traditional code generation!
4. Finally, I hope there will be an easy way to augment Roo scripts to generate the Maven POM and other artifacts based on your own environment/standards. We have our own repository and parent poms, so it will be ideal to just extend Roo to generate the POM based on those instead. This is just an example of the types of extension we might do.
Anyway...great stuff and I look forward to hearing and seeing more!
p.s. BTW, what's SpringSource's driver behind Roo when they acquired Grails? It seems to be a conflict of interests.