Keeping the Air until Apple no longer supports it, could care less about the fingerprint lock and the rest.
If Ipad Air 2 is just finger print + A8 and a few more tweaks like Ipad 4 over 3 will you stick with Ipad Air? Oh I reckon they will do a gold Ipad Air and that will be the final change for this year.
I skipped the Ipad 4 as Ipad 3 was almost the same.
I don't really like the feature with my 5S, hardly use it so it's defo not worth the upgrade.
I'll keep the air til my ac+ is about to expire. Get a replacement, then sell new in box sealed