StrangeAeonz: My guess is that all sounds have a flag if they have subtitles or not, so patching all sounds in .uax file wouldn't be simple.
I also tried patching Engine.dll to ignore subtitles flag and it works. Unfortunately the game crashes when loading levels/save game.
I was mostly talking about "blindly" creating a patch, given that the uploaded "Voiceover.uax" file works, from the diff (or some more clever algorithm) of the two files (original and modded). So, I'm probably using old tools for this job, but NSIS3 has, for example, the genpat utility that will create a binary patch, which then can be made to be installed via a NSIS script/executable installer. From a quick test this patch comes to about 25KB size.
But you're right. If someone were to fully recreate the process of setting all the voice sounds to have subtitles, from scratch, to make sure that everything is as they want it, then I wouldn't I expect that to be simple at all.