Not necessarily, Shell produces a Euro 0w-40 with no PAO or AN's. Is it easier to do with PAO, and AN's? Gotta be, otherwise Castrol would do it, as they don't appear to use PAO unless they have to.
Pour points of the GTL bases don't approach those of PAO, but you are right in that they are better than your average Group III. I'd have to bring them up, but I've posted the specs for them before.
All SOPUS oils, synthetic or blend, have very low pour points and they certainly DO approach those of PAO! Pennzoil Platinum HM 5W-20 is rated -51C as is Quaker State 5W-30. And since solubility of GTL is rather poor and rivaling that of PAO, they would almost certainly have to use some type of ester and Group I blended in, no?..
We really don't have Shell Ultra Helix 0W-40 here, but Pennzoil Ultra Platinum has a -51C pour point...