Haswell refresh will have the higher-end CPUs with solder instead of the IHS paste, but nothing in the way of DDR4. We'll have to wait for Skylake for that to happen. Broadwell still has a DDR3 memory controller.
None of the memory manufacturers were ready for any kind of ramp-up in production and up until a few months ago Samsung was still in the testing and validation phase for their memory chips. And they would only be able to sell DDR4 to enterprises for server use and to high-end consumers who were buying the Core i7-skinned Xeons on the LGA2011 platform. Moving to DDR4 right now doesn't make sense because DDR3-L is still good enough for mobile use and doing a die shrink and a IMC change would have been a tough job.