Well, when a server operator chooses between the new and the old codec he isn't deliberately disabling HLDJ but simply choosing between an old system with worse performance and quality and a new one. So we can't really say that implementing a new sound broadcasting system would be going against their wish to disable it.
One major problem i've stumbled uppon while testing alternative methods was the "operation". We usually have to set the file ready, then start broadcasting through mic, then play the file, then stop broadcasting and then stop playing the file. That's about... an awfull lot of keys being pressed just to play a simple sound. The easy method brought by HLDJ isn't something that can, at least directly, be transferred to other games and i think it's definitely worth keeping.
It would, indeed, be an insane ammount of work, specially for a non-commercial project, to reformulate the whole deal to make it compatible with the new codec. Nobody will blame you if you feel like it isn't worthed.
If you feel like it is, though, just let us know and we'll try to help in all the ways possible.