Personally, I think seniority should apply for vacation accruals, boarding priority on non-rev travel, and things like that. But it should not govern everything in life, and especially not pay.

Year 1 pay at US airlines should apply to newbies fresh outta flight school with no experience.

I think Emirates has a decent setup that I think would be a good starting point in the US. The problem is that US pilots are too entrenched in this seniority game to ever consider change...