Well a first time homebuyers credit is, at best, a symptomatic treatment for the fact that house prices are too high. Unlike actions that would lower prices or at least allow them to fall, it leaves the boomers, speculators, and others that have profited from appreciation sitting on their gains.
I admit that unlike 2007, I have no idea what the reason is that house prices are so high. I tend to suspect that just like then, excessive Wall Street money is somehow the root cause, but the linkage is not obvious as it was then. I mean a house is always going to be expensive, but housing costs compared to incomes are higher than is usual.