Playing copyright games

We have just read about game companies asking for boardgames Scrabble and Boggle to be taken down from Facebook, as it is deemed that such games are too close to the original version of these boardgames.

Protecting game format has also been an intriguing part of copyright, primarily because copyright famously "does not protect an idea but only the expression of the idea". So, just because you've invented a game where the winner is the person who accumulates the most points, does not give you any protectable rights.

Therefore, game designers now create games with "twists" and other visual elements in the hope that this will provide them with some protection. This makes the elements of games, which deserve copyright protection, notoriously difficult to identify--question is, if a game's elements can be changed and with only some elements similar, would this be sufficient to constitute a protectable game format?