Originally Posted by
^OvO^
^^^ This and possibly this :
As someone said whoever have the copyright probably is planning to make a Total War style game (with campaigns and battles) so eventhough the mod itself is free and did not generate any profit, to play the mod one must purchase a game which is not owned by the copyright holder. This will cause potential lost of income as people most probably not buy their GoT game since people already have a similar product like this mod.
This is the same with MERP since the game the WB game producing maybe competing with Skyrim so that the profit from people playing MERP will go to Bethesda rather than WB. The various LOTR mods for TW probably wasn't touched since the games are different genre though they are within every WB's rights to ask the same treatment.