Firstly, I don't see what bitcoin miners are producing other than bitcoin. Heat, perhaps? Bitcoin can be part of their revenue, but it is their production of it that pays their bills. Let's get this in order: first, their production (they are producing bitcoin and heat, nothing more) drops by 50% on the bitcoin front. Then their revenue is reduced if they keep selling the bitcoin at pre-halving prices (if the halving has not already been priced in, as I think was the case when bitcoin was selling at about $12).
Supply and demand. Supply will be reduced 50%, their demand will possibly increase, probably stay the same... unless something really bad happens, I don't see Bitcoin's price trading at below [insert the double of Jan 2016 price here] March 2017. My point is that I believe that bitcoin will follow a similar patter of a leap in price before the halving, followed by a crash, then a rise again (trading at some prices for one last time).
Litecoin has replicated this pattern, a pre-halving pump to about $8, followed by a dump all the way down to $3. It's remained under $3 afterwards, but I'm confident it's traded for under $2 for the last time.
Here's what I think will happen. We'll start 2016 at about $300, there will be a pre-halving pump all the way back to $600, then back down to $400. Afterwards, the price will change in some manner (ether stable or not), until we reach $700-$900 by march 2017. And that price will be the new norm.