Speaking as SP, literally everything?
My damage gets dispelled.
My every CC gets dispelled (Stun gets dispelled, Psychic Scream gets dispelled, Mind Control gets purged and even if not, I have to stop doing damage to use it)
We can get interrupted through our 4 sec immunity. It also drops if we do any offensive spell
Zero mobility / Zero gap openers / Zero snares and roots - In a world where most melee have insane mobility, many gap closers, ranged snares, ranged interrupts, ranged stuns, ranged incaps, and so on - and add now the covenant stuff like spear and abomination pulling you back endlessly for its duration, on top of the baseline abilities
One of my main CDs can get offensively dispelled~
My defensive heal can get nullified with Cyclone/Imprision
Anti-magic Shell immunes our full toolkit cuz it provides magic immunity for its duration and can’t be mass dispelled. There are other “immunities”/Semi-immunities most melee have
Most melee can reflect back our dots to us (warr reflect/intervene, monk diffuse magic, DH, etc.).
Dot dispell, interrupt, semi-interrupts/stuns, immunities (like AMS, reflects, Grounding totems) etc. in a perfect rotation makes playing a caster as SP a living hell
(and before the typical brainless chicken come in, I’m not saying SP is bad. I’m saying it’s frustrating to play as - now slightly less so than previous expansions - as our entire toolkit gets countered)