I've actually solved this one on my own, but it took hours, and I can't find any info on this problem when I search, so I'm hoping this post saves someone some time and effort.
So, when launching DCS, prior to reaching the main screen (the one that lets you into Settings, Mission, Multiplayer, Instant Action, etc.) there's a brief loading screen with a progress bar. After today's OB patch, mine hung at 10% and wouldn't advance. Had to task kill DCS (so, technically this is a freeze, not a crash, but I think it still belongs in this section -- feel free to move it if I'm wrong about that.) I did the usual things (disable mods, delete fxo & metashaders2, run a repair, reboot) to no avail. I looked at the log, and found this:
ALERT Dispatcher: Error starting Game GUI: error loading module 'gui_map' from file '.\lua-gui_map.dll': The specified procedure could not be found.
Deleting the lua-gui_map.dll file in the root DCS folder solved the problem for me. I ran a repair afterwards, because I was actually expecting the file to be needed but corrupt, and wanted the repair process to get me a fresh one, but it didn't replace the file, so I now believe that step was unnecessary. The last modified attribute on that file was May of 2016, so it's clearly quite old, and probably not going to cause any issues with people who have downloaded the game recently, but my DCS install is very old (the install folder is still called DCS_15OB, if you can believe that.)
In case someone else runs into this issue but doesn't find their way to this post, I suggest that the next OB patch/hotfix check for the presence of this file, and remove it if found.
Viking355th's post in DCS freezes at 10% on loading screen was marked as the answer