I didn't mean to imply otherwise; the changelist is indeed impressive. I just thought it was an interesting point of comparison.He did much more then resolution change.
As to what's possible: There's very little that isn't, with enough time and effort, but time especially is in short supply. Speech is something I've considered in the past, but it would require users of the patch to track down and acquire the speech files. I'm trying to be careful about not distributing anything belonging to rights holders. I could make things easier for players by shipping pre-patched game executables, but the original executables belong to EA, and I don't have any kind of license to redistribute. For the same reason, even though wcdx is open-source, I don't make my IDA databases available (which unfortunately makes it difficult for a hypothetical third party to see what's actually being patched).
Wcdx is licensed under a permissive open-source license and always will be. Part of the reason for that is to make adoption by GOG as easy as possible, should they choose to do so.