If you don't think the mini is to small for you then it is of course a worthy update.
A5 vs A7 processor in the new mini and you get the retina display.
I also got the non retina mini after my iPad 2 but after about a half year the screen appeared just to small for me, so i upgraged to the iPad 4.
The mini is a nice device but you need to considere that there is only a price difference of about 100$ for the Air.