Go for it. An announcement for an upgrade may come in 2016 Q2, but you may have to wait a month or two for the machines to get in stock. The Macbook Pro 2015 with dGPU didn't arrive in Norwegian Apple retailers until autumn 2015. USB-C still very young, you may have to wait until 2017, when accessories and other stuff gets USB C.
A new thinner redesign may make the computer lighter, but thats at least six months down the road. May only be provided with integrated GPU, so if you need dedicated graphics you may as well jump on your current offer. Skylake is only about 5-6% faster than Haswell on average. You can't wrong, except if you may want the redesign for portability.