Most of the suggestions involve toning down JLI's damage to cost ratio: pushing them up to 280-300 MP is the usual suggestion, with others involving toning down their ambush and sniping bonuses or increasing their munitions cost.
But what if you left their damage alone, and toned down their durability instead?
- Jaeger Light Infantry squad size from 4 men to 3.
- Sniper Rifle unlocked automatically.
- Possibly increase their range slightly.
This'd keep JLI's performance pretty much the same in the role they're designed for: sitting at the back in a cover fight getting snipes, with other infantry screening for them.
However, they'd be more vulnerable to their counters (CQC and vehicles), making spamming them not viable at all. You'd need other squads to screen for them, much like protecting a sniper.
You could do something similar for Pathfinders too: drop their cost substantially, but reduce them to 3 men. That'd make them high damage, high LoS recon squads that can dish out a lot of damage but really don't want to be taking fire themselves.