Sure, if that was the fix we were planning to make, it would be quite simple.
As for the files and edits we hope to make, its not even that we have issues making the changes. We don't physically own the files. We have requested them and that is working through channels. WOTC is discussing how updates should be made: Should they go back to the authors to make changes (since they are now getting $ from the DMs Guild and changing them without their say is kinda questionable but might mean some authors choose not to update)? Should the Admins do it gratis without any pay outside of their normal position? Should WOTC find someway to pay some one (which might mean waiting for a new budget cycle)? Should we just throw it out to some volunteers like you suggest (and make them sign some sort of documents about destroying all copies afterward and not posting to the internet and some how potentially making them liable to the author if they do)? Turns out it not quite as easy as Yeah, just let me open a file and alter a line of text, resave, and we're good.
None of the above are great hurdles.
Have the authors do it? Probably best option.....I can't imagine why they wouldn't want to update the adventure to state the current DM rewards.
Admins do it gratis? fixing all the files is an hour maybe two, so not unreasonable. Especially so since the positive effect for DMs will we hope be quite nice. DMs all spend many hours running gratis.
WotC fix? I'd hope, given the success of D&D, that the tiny cost to update a few dozen adventures to the new DM rewards scheme would not rise to a budget line and waiting for the next budget cycle.
Throw out to volunteers? Sure, I've offered one who'd do all the work. Easy enough to get him or whoever volunteered to sign an NDA.....they've been used by WotC many times for a variety of projects.
I'd understand if there was a response like "our new DM rewards are so cool and varied we can't simply add a blurb to the season 4 pdf guide" but to not adjust the prior season adventures to cover the (hopefully) higher DM experience points and gold pieces?? well I remain mystified that this is an issue. Given the number of DMs who have expressed dissatisfaction with being unable to somewhat keep pace with their friends once games are in tier 2....I'd think WotC would be excited for the opportunity to provide the fix.