https://bugs.winehq.org/show_bug.cgi?id=36139
--- Comment #13 from Adam Hirst adam@aphirst.karoo.co.uk --- Ah(!), false alarm.
It seems that a part of the solution was adding an optional dependency to wine on x86_64, namely lib32-libxslt. After installing that (which pulled lib32-libxml2 as another dep), vcrun2010 installs just fine.
Sorry about that. This particular issue now seems to be fixed for me.