All season tires don't grip as well in the snow as a winter tire. Nor forward or reverse.
Performance all season tires don't compare to performance summers in the slightest sense.
I don't understand how having dedicated seasonal wheel/tire setups on an AWD car would be an oxymoron. AWD refers to a driveline... power is delivered to all four wheels. Tire demand relates to the traction that wheel will put down in a given situation... My point being that a driveline does not dictate what type of tires you need on your vehicle. Having four wheels supply power to the ground does not give anybody an excuse to run less than adequate tires. You may have twice the chance of getting started, but it will not help you stop any faster. Nor will it help maintain traction through corners much.
For what its worth, putting "performance" in front of "all seasons" is more of an oxymoron than your example.
Nobody said that you HAVE to run dedicated winter/snows. Subaru put performance summers on it to make the car more enjoyable to drive most of the year (or all of the year in some regions). You can run whatever your heart desires, provided your hood doesn't end up in the back of my car. It's not internet jargon (or hyper BS), its an easy way to have the best of both worlds.