The biggest issue that I can see with this is the "extractor" replacement exes. You drop them in, and they dump all the content/scripts from the game. Thats why I was pointing out that instead of simply "DRMing" in a DLL, you'll want the DLL to be capable of withstanding a simple extractor swapin - that is, give it control of something that your scripts don't have, such as a feature that it can refuse to provide, rather than a simple callback which can be snipped out and leave you back where you started.
The "security" of the rgssad, or the Game.exe, is entirely compromised. The only way to secure your game is to move part of it out of both of those, into, say, a DLL as suggested above, or a Java archive (which I did recently; still compromisable but requires an additional skill set on top of familiarity with rpg maker products), or better yet: something else entirely.
Just don't forget that the best DRM of all is the alternative to DRM- making people WANT to, rather than HAVE to, support you.