This is just my personal opinion...
If you need a computer for gaming purposes, and a computer for work purposes, and can live with having two computers, I would recommend
not making the gaming machine a Mac. Most of the gamers I know that also love Macs eventually settle on two computers: a Mac for everything and resource-light games, and a gaming laptop/desktop for gaming (it sounds like you already have one you can use, but not sure if you plan to keep it or not?) Even the fully specced out MacBook Pro 15 has some major limitations in this department, presumably less so hardware than certain support aspects, but also in a sense that Macs have never used GPUs oriented toward gaming. This review is rather harsh, but demonstrates some limitations over some Windows-oriented gaming laptops...
I use VMs constantly and the MacBook Pro might be the best virtualization laptop out there...so for work usage it is great - reliable, refined, reasonably powerful, consistent, and usually with a long service life. So I'm not saying to not get a Mac. I like OS X more than Windows 10 (and I like Windows 10 quite a lot,) and I love the wide range of free and paid Mac Apps that offer premium services/support, such as OmniFocus & OmniGraffle, two Apps that played a decisive role in me organizing and eventually completing my Thesis. Those Apps have no Windows equivalents. Heck, I have a VM on my Mac of Windows (ONE...as in the command line premiere) that runs flawlessly as if I were teleported back into the 1980s when Bill Gates had his hippie haircut and was getting arrested for driving 3x the speed limit.
One exception might be if you are willing to spend the money on an external GPU, as you can currently use them with Windows via Bootcamp. You would kill two birds with one stone here, with what is often earlier/better developer support via Win 8/10, and a more capable GPU that is better suited to push those high frame rates on such an insanely high resolution screen. Even more so if you are driving one or two hi-res externals, something like a GTX 1080 is what will make high-res, high-detail, high-framerate gaming viable. If going this route, I would recommend the 2.9 CPU to get every ounce of processing power you can get, as the CPU would likely then become the bottleneck given the specs of the other components. While an external GPU would be expensive, it still might be less than buying a second rig just for gaming?