Seniority systems are not the problem with pilot pay, its lack of resolve and successful anti union laws/court rulings and, sad to say, lack of (collective) community within our own ranks.
Want to see what a non seniority system looks like? Already been alluded to in a earlier post; go read the Corporate forum, read the posts pertaining to pay vs seat and equipment, than compare it to airline pay. Oh yea, also ask about time off. You'll hear some good stories about great pay and time off, but you'll hear a lot more of the opposite.
ALPA, unions, and seniority lists may have their faults. Regional pilots are under paid, but I think your looking in the wrong place to paint the unions that represent these pilots as to why the reason things aren't better.
Airline management's ability to whipsaw different airline/pilot groups, flying the same equipment on the same routes but under different (competing) contracts is the real problem. The Comair strike educated the industry about not letting any one contractor have too much power . The industry learned and now every legacy airline has multiples of feeders, all biding against each other and all (at the labor level) powerless to force change with a strike.

Thats not the fault of the seniority system nor the lack of interest in unionized pilots for better terms, its just the way it is.