It's silly to think that there will only be improvements from one side or the other when it comes to performance and utilizing the hardware. All this developer was commenting on was that there are some issues now that may be tool related for Microsoft that are causing some difficulties and that as those issues are resolved over time, the issues themselves will be remediated. It has NOTHING to do with Sony and their tools or hardware. And OF COURSE there will be improvements and better optimization on both sides. Will that be enough to make a visible gap between the machines? I doubt it will do much, but it IS possible.
I just don't understand how people get in the mindset that "yep, MS will have better performance as they improve things, but Sony is already good so they won't improve at all. Yay Microsoft!' Or vice versa. It's just an ignorant attitude. Both machines will have improvements over time. By the time the generation is 3-4 years in, it should be pretty much there. Of course, that's about the time we're going to see more MS exclusives as well, so that will be good news for Xbox owners!
Just chill on the tools thing. It's not a zero sum game. It's not all or nothing.