I see no point in restricting mod tools; nobody will buy DLC anyways (I mean come on, let's be honest here), and I'm sure many people would be on board of mod tools were announced. I know I am certainly one of those people. If Crytek is going to be noble and give them to us I will gladly pounce upon the opportunity to reward and thank a developer that will do so.
In fact if mod tools were released I might be so pleased with the game that I might buy DLC anyways.