This isn't a series like Assassins Creed, Final Fantasy or even Star Wars where countless people have had their hands on the lore this is a single creatives vison.
I get the point though. I'm also bummed out by the exodus. I love MGS and I want to see what he can do on that engine given enough time. MGS5 was great but felt like Konami told him to cut it short and GTFO.
It's a real shame that Konami is probably going to euthanize it after a few quickie moneygrabs from the handful of interns they have left from Kojima's team.
A lot of open-world engines have pretty severe stutter problems (examples: Fallout 4, GTA:V, etc), and Fox Engine's performance is fantastic. With MGSV I get 60 fps locked with 1440p and 1.4x DSR at max settings on a GTX 1080. And it actually does look really good too - a chopper extraction with a sunrise over the desert will startle me every now and then with how great it looks.
I have a few complaints but they're fairly minor.
* Some weird bayer-mask alpha blending effects (example of a similar problem in Witcher 3: http://i.imgur.com/8neiqOg.jpg ), which are solved by running at 1.4x DSR, which is easily doable with this engine
* 60 fps locked physics - c'mon, really?
* Clipping planes cause bullets to abruptly stop working at 250m range, which MGSV tries to hide with map design by breaking line-of-sight, but it's noticeable in some desert/plains areas with longer sightlines
* Online play has rampant cheating. Gotta design in security from Day 1 if you're going to do it... and FOB combat was obviously hacked in by a couple interns way after the fact as a money-grab.
It's certainly not up to the graphical quality of Witcher 3, but it's not bad either, and performance is very good for the quality (especially given that open-world engines are tougher to do well).
With FreeSync or Gsync or Mobile GSync it would be very playable on an APU or a low-end discrete laptop graphics chip. Can't wait for consoles to start driving FreeSync adoption in the HDTV market as well.