You're right to wonder "whether the "short and fat" argument will stand the test of time and whether the hoopla is simply a ruse to get me to trade off my now obsolete M70s chambered in 270 and 06 and 338." It may well stand the test of time, but even if it doesn't, it's still a move to make you want something (specific) that you don't have.
Theoretically at least, the shorter and fatter case has something going for it. The Law of the Inverse Square applies to how efficiently the primer ignites the powder, but the real-world value of that improvement may be too slight to make the cost of a new project worth bearing. My favorite line on this came from my friend the late Homer Powley, a remark agreeing with something I'd said about how often we know that a factor has some effect but tests show that the effect is negligible.
"Yes!" Homer said, "The moon affects the trajectory but not enough to worry about."
