Simply put, there's going to be no reason for Pathfinder to get picked other than preference. Deteriorating abilities, a passive that's soon to be no longer unique, and reduced team mobility from a Legend that's 2/3 built for team play all add up to no real reason to keep picking Pathy at all – except if you really like him, of course.
A solution? Using Pathfinder's zipline for 3 seconds (a super high-risk action with the current zip mechanics) gives anyone who uses it Wall Running for 3 seconds. A player cannot fire or use ultimates while wall running, but tactical abilities will continue to work.
As soon as a player detaches from the zipline, the 3-second counter starts and can't be reset until it runs out. This will prevent wall-run/zip spamming at lower elevations. A player can jump from a wall-run, but if they do not then gravity does gravity things.
If Pathfinder is going to be slowly picked apart and made less viable, then the "side grades" patterns should continue to include literally anything to make it worthwhile to do anything but shoot as Pathy.
A Pathy fan with 6,000+ Pathfinder games.