Title should read: mike ybarra "The XDK is not complete and we’re still working on it."

What does it mean?

Well that developers might still have a tiny bit extra juice,
they can make use off in the near future compaired to right now.

How will this effect anyone? it wont.
By the time the Xbox One X launches, it ll have been done, and they ll have finished the Xbox One X patch's.

Dang and games are already looking good. I remember when DF showed Forza 7 with 4k texture/resolution and it wasn't utilizing scorpio to it's full potential. 

The kits just got out to most devlopers so there is still lots of time and it can help get the games to run at 4K Native. AC Origins was running checkboard 4K on Scorpio and high setting with only being ported in a week. 

Forza 7 only uses 70% of the XB1X power.

Damn and that looks better than any game on Playstation or Nintendo.

i'm assuming this is a guess right? you can't possibly know more optimization is not possible until then.

Yeah, he has no clue. The more time you have with hardware the more you get out of it. Thus the reason we see games improve on consoles over time in terms of graphics/fps.

I don't see anything in your OP.

VGC is broken again when i posted the tweet but here is a screenshot.