Right now it is all changing very quickly and no one knows what will be senior and junior come 6 months from now.
CLT is a rather "senior" base for FOs, but as more and more senior FOs take upgrades or move over to the wide body flying, it can all change quickly. CLT could have a huge influx of new hires as more senior pilots move up.
With the new pay rates that will unfortunately be voted in soon, you will have pilots that have only been at AA for 3-4 years taking the upgrade and making $400k per year. Others will likely move to the 777/787 because the new work rules with this contract will suck a lot and you can hide better in a wide body bid status. Others will be content to just stay FOs. So, in the end, the past is really no indication of what will happen in the next 6-12 months.
It is likely that upgrades might go a little more senior, and wide body FO will likely stay at 5ish years.