Although Warners Bro never did say that there will be a Shadow of Mordor 2 sequel, most fans assume or are hoping that there will be a sequel to the game but is there really a sequel.
When the first game was released, the developer might have hinted that they might be a sequel. When they were talking about the new Nemesis system, they said that they were so much that they could have done and added that there will be more features added in the future.
The there was the whole resume thing where the Shadow of Mordor 2 was spotted in one of the resume of a stunt actress. We all thought that we might actually hear about the game at E3 this year but that did not happen.
At this point, nobody really knows if there is going to be a sequel and with the developer keeping a tight lid on the game, it does not look like we will be getting any detail anytime soon.