The meme is that an IGN review rated ORAS "7.8/10" and one of the reasons given in the rating was "Too much water". There are meme pics and videos satirizing the review.
"In terms of difficulty is it more or less difficult than X/Y?"
Well what you have to remember is that the mainstream Pokemon games are more about the game play and Immersation rather than strategy. Remember it's a kids game.