Another voice of limited experience heard from. There's an old adage that goes "Change is inevitable - Growth is optional". This is also true with cartridges. The shorter fatter cases are more efficient than the older longer designs. I am not saying the 270 Win, 300 Win Mag and many of the other old reliable chamberings are obsolete. They can kill just as quickly today as they did when they came out. But today with the fatter cases and more efficient powders you can get the same results (or close to it) in a shorter action, usually lighter rifle then you could earllier. These WSM chamberings, whether you agree or not, are good chamberings. And most will be here for years to come.
I love my .270 Win and it has done everything I have asked it over the past 35 years and I won't trade it in on a 270 WSM. But I may have a 270WSM setting along side it in my safe some day. Maybe some day soon.