SBARROHOTTOPICI'm super confused about this whole thing -- what does this mean for HUDs?
I read the entire article, and from what I understand, not much.
You can package all the HUD files into a single VPK and drop that into the custom directory, which could make HUD installation simpler. However, this would probably make customisation a bit more annoying as the user would have to extract the contents to make any changes.
That said, it will still be possible to keep the HUD files unpackaged, stored in a subdirectory in the custom directory. Valve claims this method will result in slightly slower load times, but I'm fairly certain the difference will be negligible, unless you go overboard with the number of such directories.
To summarise what I just said, HUD installation will be simpler if you do not intend to make any changes, and it won't be any more difficult than now if you do.
[note] As far as my HUD is concerned, I intend to continue shipping the HUD in the same format as now, through Git and ZIP files. If there exists a command-line tool to create VPKs, I will generate nightly packages; otherwise, I won't.