I agree with you. However I am sure the V6 will pull as hard as the V8 (especially with the 8 speed)
It may be close. But how a car feels, how smooth, and how it sounds is important to me. Also, a sc engine by definition is more complex and more unreliable- not to say it isn't reliable. Long-term reliability is unknown, whereas the 5.0 V8 seems to be VERY reliable. Think about all the ******** people do about LR's, yet I have not seen ONE complaint about motor issues after 4 years in production and many vehicles with several tens of thousands of miles.
Finally, while I welcome ANY improvement in range and fuel economy. I work 4 miles form home and I am in a very convenient location so I have almost everything fairly nearby. I will also likely put under 10k miles per year, probably closer to 8k, so fuel costs are not that big an issue.
I found estimates that the V6 SC LR4 would improve by about 2mpg. Not bad (especially as a proportion of the current 12mpg city), but it will never be a fuel sipper.