Pi,
First, you have to ignore the purpose of the transition agreement to even have the questions you have. It is merely a bridge from two independent carriers with separate pilot groups operating under different contracts to a single carrier with one pilot group operating under one contract. So it does two things - make changes to both separate contracts as necessary to prevent violation of either between the actual corporate merger and being a single carrier completely integrated, and lay out the requirements for integrating operations as it pertains to the pilots. The latter requires 3 things - single ops cert, single seniority list, and single contract. No, the TA doesn't say that the SLI must be implemented in the single contract, but as I said where else? If, IF, the contract were to come first it would have to have language specifying that senior would be determined by - i.e. the courts, an arbitrator, a seniority integration process specified by XXXXX.
Only you can determine if you feel that you have been harmed by anything in a joint contract, but feeling that you have been harmed does not an automatic DFR victory make. Using your line bidding vs PBS, that applies to everyone so generally no DFR. Just like FO's don't have a DFR case because they're paid less than CO's. But if you want to put up the money go right ahead and sue.
What stops the merry go round is either a Judge or acceptance of the NIC. Those are the only two options since USAPA eliminated anyone from having a legal right to negotiate for only the West pilots. The same reason why Cleary's mediation offer is so comical - is USAPA going to "negotiate" with all 1700 or so West pilots? Heck, it nigh impossible to get 100 pilots to agree on anything...
Jim
PS - on your "intent vs language" question. Obviously the language is important, but so is intent. Just look at the LOA 93 pay grievance - both sides know what the language says but interpret it differently, so the intent behind the language is important. Obviously, some things are more clear cut, like the min fleet language, while others are more murky making intent even more important than the language.