It’s cool how they are giving the spartans different traits in campaign but if was doing it, instead of the somewhat simplified approach they are taking, I would take it further & make it more nuanced:
Each spartan in campaign would have have anywhere between a 0%-15% or maybe 20% boost in each of following parameters, tailored to match each spartan’s attributes according to lore & to give each spartan a unique feel while playing:
-shield recharge speed
-shield recharge delay
-health regen speed
-health regen delay
-melee cooldown (amount of time between consecutive melees)
-grenade throw cooldown (amount of time between consecutive grenade throws)
-max walk speed/max sprint speed
-Sprint acceleration rate
-weapon switch speed
-minimum reticle size aka max accuracy w/automatics
-spread reduction w/ automatics
-etc., etc, etc
So take Spartan Vale for example. Instead of her being the only one of Osiris with a speed boost & everyone else having the same exact speed, have the other spartans have very slightly different speeds within a few percents of eachother while Vale is still the fastest by a big margin.
Each spartan will have their standout stats where they get the biggest most noticeable boost, but they will have other smaller differences from each other as well.
Seems better to me than just slapping a couple big stat boosts on each spartan & calling it a day.