The quantity of gen3, despite the failings in the design's efficiency, allowed enough of a margin on the project to stay in the fight for the top chip producer. Gen4 needs to be able to beat that efficiency mark and still make the large-scale quantity orders that we saw with gen3.
Can anyone give info on which of AM's chips are in current mining hardware from hardware partners (namely RockMiner)?
Whether gen 4 is good or bad, large quantities of chips will be produced regardless in order to cover the costs. As for which of AM's chips are in current hardware, BE200 is in all of them as that's the only chip they're currently making and selling. I don't think that was what you meant to ask though as the answer was simply too obvious. Did you want to know what hardware is BE200 based?
I really don't see why there is such concern for Gen4. From Jutarul's statement it appears the current concerns are with the size of the network, the cost of maintaining what they presently have or will have and the price of BTC.
When would they not be concerns?