It's a small change, so it probably wouldn't cause any major issues. For any documents that are already at rev 1 or higher, there would be no effect at all. For documents created or added after the change, of course, there would also be no effect.
The question would be what happens to documents that are currently at rev 0, which would suddenly be a disallowed revision level. My suspicion is that there would be no problem with them remaining at rev 0, and they would move on to rev 1 the next time they were up-revved. However, if you want to have all current rev 0 documents become rev 1 documents, I would make that change before changing the actual revision scheme.
Bottom line is that you should test the idea offline before you make any changes to your production vault. I maintain a test vault for just this sort of thing. You can create all sorts of 'what if' scenarios in your test vault and make sure you truly understand the ramifications of your proposed changes before you put any of your critical data at risk.
Thanks for the advise. I do have a test vault and do plan on testing this. I also plan on pushing the reason why engineeing wants this change.