I told DDRJake about double CtA several months ago as a show of good faith. I asked Florry not to use it until 1.25 under the impression that anything shown on stream would have a higher chance of getting fixed. But what happened is the other exploit I mentioned but the devs already knew about and Florry has used already did get fixed, which was double peace, while double CtA still works. I would prefer that it remains unfixed for the time being since it's a fun exploit that allows for some crazy scenarios such as an HRE vs. Ottomans vs. Ming world war pre 1500, or perhaps a sub 1600 Mare Nostrum. And of course because there are much more important problems to address than niche exploits.
Double peace was also stealth fixed, the change wasn't in the patch notes. It was pretty much only useful for cutting down big blobs during WCs, and only had a dramatic impact on perhaps speed WCs. But then Marco improved on the previous fastest WC time by more than 10 years without double peace so it turned out to be not that important after all.
As for to CoB vs. not to CoB, backups are the only way since the default backup syncs up with the main save file after 1.23 because reasons.
Yeah, I really don't understand the obsession with these extreme bugs... Exposed players like florry use them as entertainment, or like you, marco, bbq etc in extreme WCs nobody wants to do, just watch and have fun.. Normal players, first WC-use all exploits, second-I won't do "that", third-totally legit.. I just don't see a problem in that state of things..
I mean, they should be fixed at a point, but not when you have so much bug reports that the forum can't handle them.