The system is fine. The epic failure is that the company controls all the global parameters, anyone looking to switch from hard lines to PBS needs absolute and comprehensive language controlling all global parameters, ie it needs to be agreed upon in advance what those parameters are.

For one thing, require absolute respect for seniority, nobody works x-mas (unless they did it to themselves) while a junior gets it off... the system needs to re-shuffle pairings to make it work.

Global optimization is beneficial to the company, so they will fight for it. A pilot group will need to hire technical expert(s) to advise them in negotiating contract rules for PBS parameters. Do not let ANY parameter go unaccounted for in the contract. Also need blanket language preventing ANY uncoordinated changes of ANYTHING on the part of the company.

Otherwise they will quite literally create a new parameter, with functions similar to or same as one which is contractually controlled but simply give it a different name. Example, assume these parameters exist in PBS, and there values/use is limited by the contract.

Screw.Pilots
Hose.Pilots

Without contractual language covering the system cart-blanche, the company could simply create new subroutines, copying the guts of the ones they're not allowed to abuse but name them thus...

Bunny.Rabbit
Puppy.Dog


A lesser but real issue is that tech savvy bidders will be at an advantage, by that I mean if you have a computer science degree or programming experience, your mind will be better able to grasp the intricacies... it's complex enough that there's an art to it. You will have a significant virtual seniority bump compared to your liberal arts peers. No amount of training (other than years of programming experience) can totally fix this IMO. Even the #1 dude can easily hose himself for x-mas, and will typically have done so before he learns a few things.

The real benefit of PBS to the pilot is schedule flexibility, ie you can get Tue off one week and Fri off the next and so on, ie not locked into the same weekly footprint all month (although you can bid for a consistent footprint if you like it). You can also do things like load up your flying and get 9 days off and nonrev to europe without vacation.