Employer dumping is the million $ question. And its really really hard to predict. For one, there are a lot of employers who believe in offering insurance. And the penalty can be steep (after taxes and grossed up for participation its over $4000 per employee). So employers will need to make employees whole, or partially whole, with the penalty. So the economics to dump aren't there.
That being said, medical trend is a killer. And there are no silver bullets in the ACA. None. In fact, costs are going up a lot. So some employers will have no choice but to dump and perhaps raise pay a little.
The disaster isn't everyone goes to the exchange. The exchange has a lot to like. Private carriers competing. Simplified buying (in theory). Subsidies. BUT, and this is the big but, the cost of the subsidy > penalty. And the CBO didn't forecast dumping. So if the subdues cost too much, they will go down and the consumer gets stuck.
Theres 0 chance we get single payer int he next 20 years. Hell, Obama only had 35 votes for a public option when he had a super majority. So, this thing could implode.
The other big what if is what if a few JUMBO employers dump. The flood gates will be open.
My gut says there is a lot of reticence to dump. We will see a movement towards defined contribution. But, the IRS/DOL just ruled employers can't go DC and send their employees to the exchanges. Oooops.
And when insurers make the ACA fees transparent, watch out.
Last, the feds have totally screwed implementation.