Doubt it has anything to do with Huawei manufacturing the 6P. Don't think they did anything special like change the file system to F2FS. The 6P is using the 2.1 version of the 810 which is supposed to improve throttling and overall performance. This suggests that Qualcomm knew something wasn't right with the 810. Even the 6P has been known to overheat during heavy gaming and limit performance with aggressive throttling. Running stock Android does seem to make a significant difference compared to some of the bloated ROMs with aggressive RAM management. I remember the Moto G I had performed better than some phones with better specs.What exactly enables the 6p to out perform other devices that run the 810? I remember the 6p being so smooth with zero lag and pretty much performing much like a 820 easily. I also remember that it did not have any over heating issues either. Could it be due to Huawei producing the phone or is there a specific internal software change to the 6p that enables it to out perform other devices with the 810. For a long while I actually thought the 6p ran a 820 up until about 5 months ago and I was quite shocked to find that out. My new 6p is set to arrive tomorrow and I have two skins and a skinomi screen protector on the way as well for it. I always liked the Skinomi liquid glass screen protectors as I typically use them on all of my devices.
I also use skins on most of my phones. Still have the dbrand white carbon skin on the back with matte black on camera visor. Works great with the RhinoShield bumper. Probably won't use a skin on the 3T since it makes the phone a bit too thick to fit 100% in OnePlus case.