I'm in the camp that the 2007-12 period was more of an aberration than a "new normal". I don't believe the weather patterns that dominated those years are likely to return to the same extent any time soon, and the weather going forward will be more similar to 2013-15 than 2007-12.
The long term trend continues down, but much slower than we saw 2007-12. There is some evidence that returning -AMO could slow down Arctic melt as well.
Therefore, I think another year in the next few years could easily surpass 2013. And it will take a return to sustained +dipole patterns to see something below 2012. Eventually, I think the long term trend will win out, and that happens some time in the early 2020s. But then we could easily see a big bounce back again, temporarily.