Framer,
Personally I think it’s a very workable and fair idea. It preserves the status quo, no pilot in either organisation is disadvantaged, and longer term opens up more opportunities for all.
The sort of misplaced protectionism some have with regard to Mainline is exactly the circumstance that locked AIPA out when Qantas bought Impulse. Had those pilots been brought into Mainline at the time, flying their 717s at the bottom of the seniority list, well, ...