Yeah, kind of hard to nail these things down without context.
Berg K3 has replaced DX Aviar
FD has nearly completely replaced Leopard
PD replaced Beast
Theory replaced CE Shark (which was probably -1.5 understable compared to normal Sharks)
Here I'm saying I swapped out a Beast for a PD.
But the Beasts I always threw were original molds (X wing), so more like 10/5/-1/3, and max weight vs the current rating of 10/5/-2/2.
And the PDs I now throw more are lighter weight (165-168) at 10/4/0/-3.
Over like a ten years period at least.
Not hard to see how a change like that might happen with improved form and power alone, or even from the change in weight.
And a Valk is not hugely far off either at 9/4/-2/2, since I too have had way stable Valks that were more -1/3 at least.
In my original post I even note how the CE Shark I love is super flippy compared to basically every other Shark out there...its effectively a Theory.
I'm even currently researching Blizzard Wraiths and Destroyers and I might as well just bang my head against the wall cause its seems so inconsistent, even based on direct experience from people.
Effing plastic, man...