So riddle me this. If people get the unit for it's recon ability then why are they spammed? Is it so that you have multiple spotters across the entire map? Having 2-3 Spares so you always have one on the field during retreats?
I'm not denying that the vision is part of it but it's pretty reductionist to say that it's the main draw. Otherwise you'd see a lot more IR Halftracks and the like built. If you're looking to make Pathfinder spam less toxic it's a lot more palatable to tweak their sight than fiddle with their combat ability because nobody likes weak scout units *cough cough* old I&R Pathfinders.
Each faction has it own reason so lets go through them.
pathfinder spam is because of the bar upgrade. Otherwise, nobody would spam them. so in this case its a faction mechanic thats the culprit not the units itself.
for the pf's its simply because volks are that bad. PF's are just a slightly better at dps but they still get replaced with obers. still pf's are rather inefficient. pit a pf against a rifle/IS/penal and the results are not pretty.
as for the pg's with g43's they are just that good. its surprising so few people are using them.
keep in mind that safe for pg's with g43' every single scout unit does less damage then a dedicated combat unit. thats why you dont see JLI spam.