While I agree that it would be surprising for Obama to repeat in Indiana in 2012, it is also fair to say that the Republican dominance of Indiana is history too. Once a state swings, certainly so substantially, it hardly ever reverts back... look at West Virginia... Once it made up its mind to vote Republican in 2000, it never looked back... same with any other state where demographics are not changing rapidly.
Oh goodness, I don't have anything like your confidence. I think West Virginia could well swing back to the Democrats in the future, given the right environment and the right candidate. Indiana's swing to the Democrats was built partly on strong ground--the economic issues of a manufacturing state, the simple fact that competing in the state gives people the opportunity to consider voting Democratic--but also on ephemeral qualities relating to Obama's unique regional appeal, youth appeal, and superb campaign organization while the Republicans sat it out. I would expect Indiana to be closer than it has been, moving into the future, but I would be surprised if Obama wins it again in 2012 if the Presidential race is reasonably competitive. I don't know how future candidacies and issues would have to shake out for Indiana to continue to drift Democratic, but I know I simply can't imagine it.
Obama won Indiana for numerous reasons (mostly mentioned above), and it will be quite hard to replicate many of those things in 2012 (for one the GOP will try harder). However, I do think Indiana has moved to become more competitive. Marion county has moved quite drastically towards the Democrats and the surrounding areas while still GOP aren't nearly as GOP as they once were.
Its still a generally Republican state, but I think its a state that the Dems have a decent chance of winning in the future with a solid victory on he national level. A landslide probably isn't needed.
