My feeling is for asking $499, they better be cognizant this needs to be the cadillac of consoles in every respect.
12GB and 875mhz GPU may not make it a slam dunk to be so, but would go a long way towards helping.
Imo the issue is not the specs but indeed the price, 499$ is too much when it seems that avoiding the overhead (power and costs) of GDDR5 was a driving force in the development.
IMO Durango is a poster child for what an over designed system is, I can't help but have a sarcastic smile on my face when I look at the length MSFT went into with regard to "noise" for example.
It seems to be a down fall of MSFT at the moment, they over think details, like the noise Surface does when you use the stand or connect the keyboard. It is nice, the product might feel great, etc. but they are loosing track of more important factors, like price, time to market, market trends (obvious focus on screen resolution for example, one could add the raise 7"/8" tablets), and I suspect their time to market is awful (and the associated costs super long and costly development times, etc.).
Actually I think that the main issue is indeed time to market, they are facing great challenges, they want to do great things, but in that attempt at perfectionism they are too late, their products lag the fast changing trends of the market, they do because their time to market is too long.
MSFT incredible focus on TV implies to me that lot of the decisions were take at a time when Apple or Google TV fate (pretty unsuccessful products, if not unsuccessful at least irrelevant) were unknown and before more integrated efforts as Smart TV failed to gain much traction. It is a sign of a way too long time to market and too inflexible design process.