I don't think the additional 3-400MHz is worth the premium myself, but it does bring frequencies more inline with Pentium/Celeron CPUs. What I'd really like to see would be a hypothetical 3.9GHz version with a 65W TDP. That'd make a (too...?) good competitor at the $70 mark for people who don't need IGP performance, but need to run basic applications that are still (mostly) single threaded in nature.
Adding 2-3CUs is unlikely to bolster performance enough to be a meaningful upgrade. The 2200G serves that purpose admirably, and has 4 real cores. As others have pointed out, a more performant Athlon IGP would cannibalise 2200G sales.
Ultimately I agree with whm1974, the Athlon is either for users on a very tight budget* or those (like me) who need a 35W TDP.
*Who'd otherwise be stuck on some Pentium/Celeron with HD510 or 610 IGP(!). Which is what Intel offers at this price level. Compared to those, the Athlon is a graphics power house. I don't even want to mention the small core SoC graphics...