I hope you will redo this face-off when the HP ZBook 17 G3 has been tested ... and this time include the Dell Precision 7710 (which you have already tested and which is more deserving of a slot in the mobile-workstation class than the MSI).
Also, on the ThinkPad P70, is it not possible to swap in a second 2.5" drive for the optical drive by using an UltraBay adapter? If so, and the UltraBay drive SATA port operates at top speed (which was not necessarily the case on some older ThinkPads), its potential storage capacity could fairly be called 2 x M.2 + 2 x 2.5".