I have yet to see any real "positives" with the new SAs...

several reasons.

1) only the 270 WSM offers something new ballistically.
2) In north america (90%+ of the market for them I suspect), the only hunts where they would offer the shooter anything beyond what is already available are sheep and goats in the mountains, where weight is such a huge issue. and even at that, only a 270 and 7mm are needed (although a case for a true .257 short MAG could be made... the new 257WSSM is NOT a magnum as it only replicates the 25-06 velocities.
3) the accuracy benefits are very very minor, and not well substantiated. nothing a good reloader couldn't accomplish with a .308 Win.
4) Feeding issues... have you SEEN a WSSM????

if I'm a marketer, I see one application, really. featherweight or extreme-weather rifles in 270 or 7mm... otherwise... I don't see it. the 300WinMag is a very well-respected long-range target round, and the 308 does whatever the 300 can't do.

to me, the whole "short-action" question had already been answered though. it was the 7mm-08. short action, great ballistics, good bullet selection, right size for the game at hand....

the only other viable uses are things like ELK hunting... yeah, I want to shoot a 6.5lb 300-mag! NOT!