Wrong. Core i3's are superior to fx 6300's and fx 8350's in gaming, even if you overclock the latter. That's a fact as of now and there is no indication why it would change over time. Cpus are not wine, what's bad now won't magically become better over years.
While the fx 6350 is about 20% faster in perfectly threaded applications (rendering videos, uncompressing files, doing math calculations), in the remaining scenarios including gaming the i3 is faster due to its about twice as high single core performance. Neither are perfectly suited to gaming, but a fx much less than an i3.
And if you're thinking of getting a fx 8350 - or overclocking the fx 6300, for the same money you could get an i5 and get even better gaming performance than a fx 9590. The fx line is great in what it's good at. But for gaming, fx chips are simply horrible choices.
As for "future games will use 8 cores, becuase the are ported from console to pc", that's simply not true (the latter) and completely (highly unlikely) speculation (the former). Consoles work completely different from pcs, developing games for consoles is completely different to developing games for pcs. You can't just compile a console game for pc and it will make efficient use of resources, contrary, it will be absolutely unplayable (if it even works). As for future games being developed for 8 cores, that is unlikely, at least in the next ~10 years or so. Intel doesn't offer 8 core cpu's in their mainstream lineup, only amd does. With four core cpu's getting into the mainstream lineup of both intel and amd, it took a good 8 years before game got even remotely close to making efficient use of four cores - many still don't yet. And even if it would suddenly happen, there is no reason to believe a fx 8350 would do any better than an i3 in those games, unless they are also very resource heavy.
All in all, chances of an i3 outperforming a fx 8350 for the majority games for the next 5 years (which is about the point you should definitely upgrade) are about 95%. Chances they're getting even probably 4,9%. Chances of a fx 8350 suddenly outperforming an i3 - at best 0.1%, I'd say even much less. The scenario for that to happen is just too unlikely - and goes completely against what developers do (and should do). No sane developer team spends effort of getting performance heavy parts of their title to run on 8 threads with equal load, which takes a lot of time, introduces exponentally more scheduling required for... nothing but lost time and money in the end, when they could just work with what's available in even low budget pc's (i3), spend a lot less time developing, having it easier to expand the program as well as eliminating bugs and after all the same performance with the same income.