I have to shame-facedly admit that I ended up swapping every one of those horrid Athearn trucks for not-even-remotely-prototypical MT bogies.
I got fed up watching my Athearn MP36PH spin its wheels while trying to pull a meagre 6-coach GO Transit commuter train. I decided that an easy-rolling rake of useable coaches was preferable to seeing shiny disc brakes on wheelsets that refused to rotate.
I too have my fingers crossed that the improved trucks will be made available for the older bilevel cars. If Athearn were to do the right thing, they would provide those new trucks as a customer loyalty initiative, but I’m not crossing my fingers in hopes of that!