I think AMD is changing their strategy now since 28 nor 32nm processes are going to be viable this year at all from either Foundry Company or TSMC. The intention is to use Southern Islands to compete with GTX480 and its possible refresh. I highly doubt there will be any refresh of 5870 series at this point. Looks like a "hybrid" northern islands and evergreen card (or 3 of them rather) are going to come out in 2010 and 2011 is when 28nm new gen will arrive:
http://www.xbitlabs.com/news/video/..._Different_Suppliers_Hybrid_Architecture.html
Yea, AMD probably knows that Nvidia's dual GPU part (if it ever comes) may end up faster than the 5970, but based on the power/heat/noise 'issues' that the GTX480 has AMD probably isn't too concerned... imagine two of those GPU's and twice the DDR5. Even if a GTX480x2 type of card comes into existance AMD knows their 5xxx cards will still sell like mad most likely. They have no incentive to rush out a tweaked/refreshed part, they are probably satisfied with how the current line up matches up. And being that it might be some time yet before 28nm is viable I doubt they want to have nothing new to offer between now and that time.
OP, I've had no problems with a GSOD what so ever. Infact I've had no problems at all in the 5 or so weeks I've owned this part. That's not to say that issues like the GSOD don't or didn't exist. But, I'm willing to bet the problem is pretty well taken care of via driver updates by now. Enjoy your new card, I'm very happy with mine... the price was a bit steep in my opinion, but the hardware itself is very good.