These abilities are officially known as "Hidden Abilities", "Special Abilities" or somesuch, not "Dream World Abilities". We've already been given event Pokémon with their hidden abilities and there are even two examples of Pokémon found within the game that come with their hidden abilities instead of the standard. There's nothing to stop them including more ways to find Pokémon with different abilities.
I feel that the Dream World premise can be refined to integrate better with the games. The Nintendo DS is an old system that can barely manage to keep up with internet communication, as we can see that it takes forever to do a Game Sync. On the other hand, the 3DS is a far more powerful piece of technology that could easily support connecting to the Dream World servers and being able to do everything from the 3DS itself, which would allow the Dream World mechanics to be integrated with your game a lot more cohesively.
As it stands now, yes it's a pile of rubbish built around cheap flash games and a house decorating idea that's nearly pointless because it's so cumbersome to visit other people's dream worlds.