I think the most elegant fix would be to give Pathfinders some kind of T-70 like Recon Mode that toggles better their current sight range with the Sniper Critical being active. That way they retain their utility but you are choosing between them being a spotter and a "mainline replacement".
Ideal fix would be to remove pioneer extra vision. It was given when Ostheer was in a really bad position but today it doesn't make anymore sense for them having such free ability on cheap starting unit.
Then removing every vision range abilities given to any unit that isn't a reco unit. Tanks and infantry alike. Keeping only the historical scope for Ostheer since it already come with a downside.
Then removing the weapon slot on Path.
In 2vs2 you must pick pathfinder because your opponent's doctrines of choice give extra vision to their tanks and infantry when they themselves aren't already picking JLIs.
How are you supposed to fight a P4/P5/Tiger when it has more armor, more vision and more penetration + arty barrage in bonus.
A KT that have incendiary round + extra vision
A Tiger ACE that can self-repair and extra vision
Command Panther that have extra vision
etc...
Well you pick a unit that also provides you vision.