Just a simple +1 of support to modernization efforts in general. It's encouraging to see that Jason & Eric had some fun together on this. Modernization, I think, helps with the fun of any open-source project, and thus helps keep everyone interested in continuing and reviewing interest in Solr. If we/others feel we can't make fundamental changes, then I think our interests (and that of contributors) will wane. Personally, I really enjoy refactoring codebases, even if it may not seem sexy to some.
I don't think we can rush into a SIP before more research/POC is tried. It's too abstract at this stage. We don't even know what framework to use yet ;-)
