Basically, some of the status effects are less use now that is why SP should improve them. I have a few suggestion on improving the status effects to put it back in the meta again
Stun - Okay
Freeze - Freeze is just a stun that deals damage, who wouldn't pick this instead of stun. Freeze should be change to:
(Deals low damage, can't use physical attacks) to be more realistic and put more strategy.
Nightmare - Not much of a use, should be change to:
(Deals 10% damage, -50% damage against dark)
Poison - Poison in reality should kill you overtime but that would make death count useless so poison should have effect limit:
(-20% attack, Deals 5% +7% per turn and have a recently poisoned status)
Burn - Let's be realistic, if someone is burning the best way to do is to pour water -- but not for monster legends. Burn should be change to:
(Deals 19% damage, -10% stamina, cured when attacked by water)
This will make Fire & Water combo rather a bit weaker.
Daze - Okay
Total Blind - So OP in my opinion
Blind - Good
Bleed - Just like poison, it should deal damage overtime at an increasing amount and remove damage reduction as it doesn't make sense.
(Deals 10% +5% per turn, bleed stacks)
Bleed now stacks meaning if a monster is bleeding and got attacked by another bleeding attacks, it wouldn't reset the time but instead stacks.
Possesion - Powerful and can change the outcome of a match, nevertheless, a good status effect. No changes.
Haste - Useful if used in the right way, might change it a bit to:
(100% chance, +15% speed for one ally)
Slow - Opposite of Haste.
This is all my opinion as I wanted the game to add more realism into it, feel free to comment anything you think is not good suggestion