I don't see how you think these changes will somehow weaken the area, according to everyone I've talked to who has experience with designs like this, it should in fact totally solve the cracking issue. An issue that only showed up in a specific batch of firearms from what I've been able to learn. This change also already exists in other CZ products, and hasn't been an issue there. As well, Tanfoglio suffers from the same issue occasionally, so it's not like it's a CZ only thing.
As for Glocks, I've seen them fail at under 1000 rounds, I personally own 1 that failed at 2500 and had to be replaced (G17 Gen III). I've got Shadows with well over 100k rounds through them that are still shooting just fine. A gun is a mechanical device and those things fail sometimes. For the vast majority of people there will be no issue with their existing Shadow 2s, if there is, then CZ will fix it through their warranty services.