It's beyond stupid to build a new rig today and go with low end intel pentiums without HT, with the hope that newer games coming out are not crippled on anything less than quad core.
So no, if you want to use discrete GPU and discount the iGPU, a cheap intel duo core + discrete is NOT a better option than a cheap AMD quad/hex + discrete. At the bare minimum, one would have to go with an i3 with HT on for 4 threads to maximize the lifespan of that newly built rig.
As for older games with single threads, it doesn't matter because anything can run them well to put the bottleneck onto the cheap discrete GPU. If you have an expensive discrete GPU, then for sure, intel i5 or i7 all the way, no doubts about it.
I build a lot of rigs for people, and I always ask them their budget range and their usage scenario, there are definitely situations where AMD's APU is the superior choice. I am not biased as you can see, in my own rigs, its both Intel CPUs.