When people think of games for tablets or smartphones most of them think of things like Angry Birds or Fruit Ninja. Whilst there's nothing wrong with these games people need to bear in mind the more "serious" games and more developers need to move this way. If app store developers focused more on developing full fledged hardcore games, and put some creativity into them and not just copy familiar franchises then smartphone and tablet based gaming could become truly great.
Games such as Modern Combat are proof that tablet's can provide a console like experience, once the controls have been mastered there is really no difference between the game and Call of Duty (sorry fanboys). Other games like Order and Chaos and Chaos Rings only go further to prove that the potential is there. Imagine if Gameloft made an original game I stead of just ripping off pre-existing ones? It could be incredible.
Of course the new iPad would have to be the leading light here. It's power and display are perfect for gaming and Infinity Blade Dungeons will likely be an even bigger success then it's predecessors. With games like that it's been proven that smartphones and tablets can do big things and with products like Apple TV it's even possible to get them onto the big screen so they are even more console like.
Ultimately only time will tell how these products will grow but with consoles on the decline something new needs to replace them and I truly think that tablet and smartphone based gaming could be that new thing.