Let me play devil's advocate here...
I'd love an M2 but it's not that special by ///M standards.
It doesn't have an S engine and not much differentiating it from an M235i. (It's still an N55)
Yes it's faster, tweaked chassis/engine/suspension/brakes etc but it's still missing the ///M soul, the racing pedigree.
It's a great car and a great BMW but what a lot of people are trying to get at is that it is not a great ///M when comparing it to ///M's in their prime.
When the s54 M3 came out there wasn't much out there that could compete. Years later it was still a benchmark... THE car to beat.
Rumours of an M2 GTS/CSL are still circulating and if one appeared with an s55 (as the M2 should've), it will be more desirable.
Problem is, it'll probably cost just under R2m and have extremely limited numbers.
Don't get me wrong, I'd love an M2 & I even prefer that chassis/shape to the M4.
However, in 10 years, if I were to pick between my car (s54 Z4M) and the M2, I'd pick the Z4M.
It's special, different, unique. The last of its kind.
(In 10 years the Z4M will probably be about the same as the M2 anyway and before you say I'm delusional, look at the price of a clean M Coupe vs an E92 M3)
To summarise, if I could afford an M2 I'd buy one, as a second car, not as a replacement.
The Z4M I'd never want to sell, the M2 I'd upgrade a few years later.
PS. At the end of the day, this thread is filled with a bunch of passionate gear heads. Calm down, we all love BMW, no need to get upset.