One potentially extremely bearish development that both bulls and most bears are ignoring is the distinct possibly of a shift towards populism in the years to come.
Bulls and bears alike assume the continuation of right-wing plutocratic economic policy as far as the eye can see -- with the Democrats being not much different from the Bushies in this respect.
But with economic and financial pressures on average Americans continuing to surge even as markets boom and a tiny elite accumulates riches beyond the dreams of avarice -- the stage is being set for a dramatic change in the not too distant future IMHO.