The I&R Pathfinders artillery isn't what needs tweaking. It's the range! They can only call it in as far as they can shoot. This means that they have to run straight into whatever it is they want to actually use the artillery on.
Considering that they aren't really good for anything else and are a rather fragile squad this is pretty ridiculous. Especially when the major can do the same from the safety of behind the lines. Why waste manpower calling in a unit that does the same thing a unit I will have to eventually get by default can do better.
Pathfinders can also cloak and come in much earlier in the game at "2" cps (actually 3).
I once had a pathfinder squad hide in the middle of minsk pocket barraging whatever defensive line he tried to make. The amount of "AMURICA OP" rage was glorious (even when I told him why it was happening). Then he got a tiger and won because US has a extremely difficult time chasing down damaged heavies.
Anyway, the range is fine as it's easy enough to either bypass defense with their huge sight range or simply crawl to the enemy. It then falls down so fast that anything with a setup time will be unable to avoid it. It's also worth noting that it stunlocks any vehicle hit.