I think that the msys2 project needs a nice front page to get better known by the public. Like the front page of mingw-w64 (http://mingw-w64.sourceforge.net/). Msys2 is probably well known by mingw-w64 users, but not by mingw.org users. At the moment the Summary page of msys2 does not even have a description.
The front page should point to the installation page.
On the installation page you offer a 32 bit package and a 64 bit package. My first assumption was that the 32 bit package would offer a 32 bit msys2, and 32 and 64 bit compilers both for 32 bit host. And the 64 bit package idem dito, but then all for 64 bit host.
After installation I noticed that the only difference is the msys2 shell (32 or 64 bit host), and the compilers are exactly the same, 32 bit for 32 bit host, 64 bit for 64 bit host. Perhaps you should make this clear.
What is the point of having a 64 bit host compiler in a 32 bit msys2 shell? On a 32 bit Windows machine this is useless.
Before I used MSYS2 I used 64 bit gcc for 32 bit host (Ruben van Boxem) on msys on 32 bit Windows. Now I have a new PC with 64 bit Windows, so it doesn't matter any more for me, but other people may need it.