on the software side, I think AMD drivers have already come a long way, and the improved optimizations from games being made for AMD's jaguar architecture can only further improve performance of AMD's single card solutions. as for frame-pacing etc etc, it is a problem that AMD has more or less been forced to acknowledge, and progress has been made and should continue in the coming months, years.
As for hardware, AMD's problem has always been heat/power efficiency. tho unlike their battle with Intel on the CPU side, extra heat output for enthusiast class desktop GPUs is not a very significant problem. but when your dual-flagship card down throttles due to heat (7990 isn't the first time, think 6990 etc), it only creates a negative company image and leaves a bad taste for those dedicated AMD fans who shelled out $2k for a pair of 7990s at launch.
Thus, I think the 23% die size shrink on 28nm for AMD's Hawaii chip makes a lot of sense. if they can match or get close to Titan's performance, but get their heat-output under control, it would eventually lead to one hell of a 9990 card; better company image, and the GPU crown. We know NV is unlikely to give us a dual Titan card, so as an AMD fan, I hope this is where they can pull ahead this round