TBH, if you want to fix it, separate pay and seniority... make a pay scale banded by flight time ranges.
For example...
0-3000 pays x
3k-5k pays x
5k-7k pays x
Etc...

Figure a multiple for flight times if you need to use something as a base, assuming you think bigger is better (i.e. 737/A320 = 1.0xflt hrs, RJs = .9x, C172 = .7x, A380 = 1.3x, millennium falcon = 52x, etc) Have a seperate pay scale for CA/FO and give each band step raises per year (cuz not flying on reserve means not progressing up the scale). Make the numbers what you want, but make it similar to every other profession where your experience means something.

Note this has NOTHING to do with seniority. Newest guy in, means bottom of the heap. Your time at brand X means nothing to your new company or it's pilots other than recognizing your experience. (Which is why a National Seniority List is a terrible answer.)