I'd contest that bit about full frame.
Anyone on full frame will be getting the 50mm f/1.4G, no doubt about it as there aren't any Nikon full frame cameras old enough to be dropping into the price bracket of anyone who'd take the 1.8 over the 1.4.
The 50mm f/1.8 is aimed squarely at crop sensor users of cameras such as the D40, D40x, D60, D3000, D3100, D5000, D5100 without in-built focus motors, so that Nikon's cheap primes (35mm f/1.8g AF-S, 50mm f/1.8g AF-S) dominate the prime market, in response to Sigma's success with their EX f/1.4 lenses.
I'd be surprised if we don't see an 85mm f/1.8G AF-S before long, to be honest. We're hardly going to be seeing any new Nikon professional lenses soon (Nikonrumours agrees) given the current economic climate and the production situation in Japan.