I would wait at this point. For $100 more when the Mini 4 is released (and likely much less if you wait for a good sale) you will, at the least, get a A8 processor, and at the most an A9 and more RAM.
Agreed. I would wait and see what happens at today's event. But, if a new one comes out, buying an mini 2 would mean that you are two generations behind. So, maybe you should go with a mini 4.