>16gb ram are pointless for 99% of users. Gpu power will not increase by 40%.GPU performance should be 40% better, which is pretty significant.
ddr4 ram shouldn't be limited to 16gb in laptops
Broadwell should take a large slice out of power consumption. It also won't run as hot. There are some other things that Apple could do to drastically improve battery life (like 40% better) as well, such as using an IGZO display.
There will not be a 40% battery improvement either, because there will be no iGZO screen.
The rmbp are all reduced in price right now. Best time to buy!