The M22v2s are ruler flat over the same or larger range than the M3s. Axiom has the speaker you describe, but you don't like it as much as your older M3s, which, ya know, is fine.
Axiom's focus, from what I've learned in speaking to Ian et al, is on getting as flat a response as possible not just on-axis, but off-axis.
As to the subwoofer issues, clearly there have been issues with the EP800, which have been/are being addressed. I don't think it's taken away from the lineup--just ask people who have working EP800s! I have yet to see a post from any of them after receiving revised, working amps, that is negative about the product!
A1400 owners? Also appear to be a pretty happy crowd.