The Wii is a testament to how casuals work. At first Nintendo made a boat load of money off casuals, and they catered to them properly. But casuals only stick around for so long. They eventually get bored of it, and fade away. To be frank, they'll never come back. The problem is that casuals pretty much want everything handed to them on a plate. Anything too difficult, and they get turned off.
So Blizzard decided in WOTLK with Naxx to make raids easy, which generally made everyone who wasn't casual, mad. So they slowly introduced hard modes, and now Heroic modes. In which Blizzard introduced essentially a difficulty setting to WoW. That in of itself was a huge mistake. Biggest mistake was introducing LFR, which was super easy mode for casuals. By doing what Blizzard has done, they have removed incentive in their game.
You'll never make casuals happy, but now the core audience of WoW isn't happy either. Cause, if everyone can just do LFR and see all the content, then why raid? Games today are generally doing this, and I'm pissed off about it. Games are fun when they are challenging, and I overcome something.
Game developers are too concerned that they may piss off their customers, so they make it easy enough for anyone to finish the game. Which is why a difficulty setting is a terrible thing to introduce to your game. Cause most people will do the game in normal or easy mode, beat it, and then throw it away.
See, Dark Souls is a good example of how to do it right. The game is hard, and it becomes engaging. Suddenly you have a reason to grind out gear, and learn new techniques and skills. It requires observation, lateral thinking, and experimentation. Above all, patience. WoW's only incentive is to beat other people on meters, and even then not really. You can kill Lei Shen, just fail at LFR 5 times and you'll see him dead, and get phat loots. This is a problem cause why do normal or even Heroic raids, when all the same loot is given out in LFR?
In my opinion, Blizzard needs to go back to Vanilla and TBC style raiding. It should be hard. It should have one difficulty setting. It should be for those dedicated enough to work with 9 or 24 other people extremely well. Cause right now Blizzard is trying to make everyone happy, and that never works out. You'll just make everyone made at you. Also, Blizzard seriously needs to fix realm population problems. I can see the reason not to merge realms, but they need to do something drastic. Without players, this game gets useless to play by yourself, which leads to people canceling subscriptions.
Either...
A. Give everyone a 1 month cool down free transfer to any realm they want. Just let the players decide where to go. Yea, they won't make money from server transfers, but that needed to stop long time ago. I mean $25 for a server transfer is extortion. It's that or spend months leveling up another toon, and then gearing it.
B. Cross Realm
EVERYTHING. As it is right now, cross realm zones have no benefits to low population realms. They just invite players from high pop realms to take resources in your realm. Cross realm should apply to Auction houses, raids, guilds, and everything in between.