It's all a bit tongue in cheek but if one looks at the domestic models of yesteryear similar movement was the norm.
A typical progression was
F27 F/O
F28/737 F/O
B767/A300 F/O
F27 Capt
F28/737/727 Capt
767/A300 Capt
The "product" at the end had pretty much done it all. If this is what the company wants then go the whole hog rather than divisively changing the seniority rules in mid stream.
In the end though I'd say the goose is cooked and one will just have to bend over and accept it, as we always do. The fact that the company didn't even consult AIPA (as far as I know) at all tells you they do not see this as an industrial issue.