I'd consider the 130 gr bullet to be the mid weight standard for the .270, and 150 gr the mid weight standard for the .30-06. To achieve the same sectional density as a 130 grain .277 bullet, a .308 bullet needs to reach 165 grains in weight. Even at 165 grains, the 130 grain .277 bullet has a much higher ballistic coefficient.
As someone on here said, the argument is rather academic. Trajectory and impact energy are so similar that the differences don't matter for 99.9% of common application. I currently use a .30-06 and have never fired a .270 Winchester.
I think my question should have been - is there any game the .30-06 can take that the .270 can't? I have a feeling that in North America the differences between the two cartridges are academic.