This is a question I’ve been meaning to ask of the core team for quite a while: Will ExtJS remain at the forefront of the manager UI for the foreseeable future and, if so, has bringing its version up to date been considered?
I realize that there were major changes in ExtJS moving from v3.x to v4, making it a difficult move to migrate. And if I recall correctly the way Sencha structured its licensing may have been a barrier too. (For a time it seemed you could only move to post 3.4 versions via a very expensive commercial license). However, current major versions are available under GPL and Community Edition these days (as I’m sure you know).
Anyway, my concern is that investing time to master the nearly decade-old syntax and structure of 3.4, with Ext’s learning curve as high as it is, may dissuade extra developers (at least ones wanting to closely follow the lead of ModX’s core). At first I wondered why base Revolution’s UI on such a complex framework … why not use jQuery or the like? But with time I realized why a non-component based library like jQuery wasn’t chosen. But I do think, short of there being a legal/licensing reason against it, that migrating to a current version would be worthwhile.