Been working on the TTF support for quite a while actually.
It just hasn't been high priority since we worked so long to get 3.6.9 done. There were 3 primary reasons for the TTF support though: 1) better customizing for mods, 2) better looking fonts in general, 3) better i18n support.
The engine does have some basic i18n support, though it is very lacking in several key areas. I plan to add UTF-8 support for tbls/missions at some point, so that umlaut support isn't as wonky as it is now (we have to hard-code umlaut translation). I also plan to add system level language detection so that you don't have to tell it to use something other than English, it will just look at your system settings and try to use that, and if it can't then it will fall back to English. The new input code, which is part of the new pilot file rewrite coming for 3.7, will have far improved support for i18n keyboard layouts and not have so much of a dependance on us-101 like the code does now.
The string translation tables aren't bad though, they just aren't used by 99.9% of the content makers. I would really like more support in this area, but since my Spanish is absolute crap, my German is so lacking it's not funny, and English is all I have left, I don't really have the linguistic abilities to do translations myself. I want to improve this support to some extent, and also add much better support for custom strings, but we need people to actually do all of the translating for that to work. Unfortunately, no one has ever volunteered to do any string translations because it's not easy to do with our setup. Of course, we won't spend time to make it any easier since there is no one to make it easier for. It's one of those chicken-before-the-egg situations where nothing ends up getting done.
If you want to help out by doing string translations (with strings.tbl and tstrings.tbl) then that would be great. The tstrings.tbl file has all strings used by tbl/tbm and mission files, whereas the strings.tbl file has translations for strings actually contained in the EXE itself. Those XSTR("", -1) things that you see in the tables and missions are for string translations, so basic support is there, we just need the strings and for the XSTR() lines to have the proper string reference (rather than "-1"). Someone maintaining a VP with that info would be of tremendous help to us. And of course that info could eventually be rolled into the MediaVPs, or just continue to be available as an officially supported, but separate, VP.
