I nearly **** bricks when I read this.
Diego is the head mplayer dev and when calls for a release, he means it.
So, far fixes for libass include fixes to the max_glyphs call. Minor, but I know that at the very least, koda would appreciate it.
As for having vsfilter 2.39e tags incorporated into mplayer, I'm working on it and lobbying hard. If you want it in the next release, you guys will have to lobby hard on the mailing list (primarily mplayer-users or mplayer-dev if you have coding suggestions) and IRC (irc://irc.freenode.net/mplayer