Steams CEG solution seems to be the better direction for this stuff, as it doesn't impair the game on a functional level. It just makes it so you can't use certain features or texts are changed to other things. Which can make a game look like this: this is a pirate copy hence the Yarrrr replacement of real text , we never disabled the game other then the text. Batman Arkham made the game playable up until you had to use your cape to glide somewhere which the game didnt allow if it was a pirated copy.
These are also crackable but more subtle and make your game act like a demo for the real product, so that when users start to complain on your forums you can tell them, to buy the full version to get ride of the issues.