I'd wait at least through October as that is the month some new iPads have been introduced in the past.
Yet, as to whether to buy it or not... aren't there still several issues with the iPad Air 2?
1) Speaker vibration.
2) The loss of the side slider for rotation lock or mute.
3) The battery life being less than the original Air (some reviewers said substantially less; others reported little difference).
A substantially discounted Air 1 would thus have some things going for it, although with its older processor, it won't be as future-proofed.
Incidentally, I've noticed in the past several months a huge upswing in attention being paid to the chip inside the i-devices. Is that just happenstance? Or, a brilliant tech leak, news leak, and public commentary by Apple to get everyone talking about the CPUs-- and thus more likely to upgrade? A different form of RDF and one that just affected my post, too!