Well, I for one would love to kick the last 32 bit libs off my system. It will feel good, like going to a site that hasn't gotten the memo and sits there plaintively asking me to make sure flash is up to date... hah! Never again baby.
I'm sure there are a tiny tiny handful of people still using a 32 bit OS who overlap the little portion of people using linux and who are aware they could upgrade but don't because of some weird sort of concatenation of dependencies that is--as hard to believe as it seems given how transparent 64 bit compat layers are--enough of a reason for them to stick it out and there is probably a small portion of them who have actually tried to get it working before deciding that it was either (somehow) more of a hassle, or they just got tired/sick/frustrated with it and went back to what they've been using.
I remain skeptical that this overlap of overlap of overlapping unmagisteria actually encloses an entire person, much less several, much less enough to make it an important enough factor to consider--briefly--if it would be worth it to hold off on moving to a new architecture for a game like DF.
I'm curious what the overlap with stuff like gentoovians and slackers and such are, now...
I can sympathize with wanting to keep a smaller footprint for your VM when testing windows stuff, I had to use a VM layer for my proctored testing software (which amused the hell out of me the entire time) because the software itself was windows only, and yeah even 7 could get hoggish in a VM.
I was also very happy to get that crap, even in a sterile contained VM form, off my system. Filthy habit really, gateway to stuff like facebook and tablet games addiction, and from there the hard stuff: crack.
Where was I, oh yeah, VM testing footprints are a thing, but again not a strong vote in favor of 32 bit support.