I really don't think this would be hard to implement to be honest...
It is hard (I can explain why if you'd like), it has very little applicability to most of our customers, and worst of all "anti-cracking" and "anti-hacking" are snake oils
. That is, they don't work -- they don't prevent hacking or cracking, or even slow down hackers and crackers.
There are good reasons for repairing installations, and we'll be including it in wyBuild 2.7.x alongside the installer-maker, but I still can't see any good reason for including repair functionality in the updater itself. It increases complexity, increases bandwidth usage (up & down), and offers only marginal benefits over including repair functionality in your installer.
Now if you're trying to prevent cheating in your games then you'll have to do that server-side. There's no good way to do it client-side (not unless you control everything from the metal, through the OS, through to your game).