a. Preserve jobs.
b. Avoid windfalls to either group at the expense of the other.
c. Maintain or improve pre-merger pay and standard of living.
d. Maintain or improve pre-merger pilot status.
e. Minimize detrimental changes to career expectations.
Objectively quantify any of those without opinionated agruments, or spreadsheets that paint the statistics the way you think it should be. No one can, as any of those are arguments based on speculation and the entire process is subjective and colored by an individuals point of view.
Everybody is different and the results could have varied from one arbitrator to the next. A process like that is fundamentally flawed, and does not comport to unionist solidarity in any way.
If a group of individuals is affected by a flawed policy, and an ineffective union, they ought to fight it because they didn't pick the policy. It was imposed on them by the political powers to be and the pet projects of a 50,000 member union that isn't a union at all and hardly an orginization.