@tangix - I have to ask... what are you looking to move to for other new projects? I did the same thing regarding using EXTJS for a project because of time constraints. I purchased a new license just to knock out a project but if I had time I would have liked to try something new. I used EXTJS in a previous job so I already had experience.

Also I really like it and have not found anything that can do what it can do... but with that said I don't think it is going to get any better and will eventually be irrelevant.