Still, Marksman and Survival, compared to any other class with any of their two specializations, are way too similar and new players will barely gain anything non-baseline while leveling up. If they do gain something for their specialization, it's almost always just a passive, which passives are only so helpful for making a spec unique.
None of my suggestions would nerf hunters, they are intended to either do nothing or buff them. It's just mostly to make the playstyle unique, not change the effectiveness (unless more effective, balancing can come later). For-fun changes.
-Marksman could receive a physical-based arcane shot, and survival keeps the original arcane shot. Damage output somehow could be balanced accordingly since it'll be affected by armor.
-Survival could receive a nature/poison-based arcane shot, and marksman keeps the original arcane shot. (personally, I think a lightning-based focus dump would be sweet for surv).
-Or any other way of making a different focus dump for the specs.
I see a lot of hunters commenting on Arcane Shot being boring for all three specs. Although marks and surv already have different shots and I would personally stress different abilities, I've seen this mentioned a lot.
-Marksman could receive some sort of far-range ability or a temporary range increase cooldown, mentioned a lot.
-Survival could take more advantage of Camouflage than other hunter specs, considering it is equal in effectiveness for all three hunter specs even though Survival looks and feels like it would be intended to truly benefit from camouflage.
-Survival could use a unique trap (possibly a shadow-based trap). Trap mastery makes it clear that SV is the trap-based spec, and a unique trap would only make sense + isn't already in the game.