There is still a lot of stuff that depends on weed being legal at the federal level, beyond just the consumer not getting arrested for buying small amounts. We're never going to see serious investment in the space until sellers can access bank infrastructure, there is no longer a risk of DEA raids, state laws are aligned with federal laws, etc.
It's not going to happen in 2015 though, unless it gets tacked onto some other crazy spending bill, which is unlikely. It'll probably happen sometime between 2016 and 2024.