Vampire spawn are both OP and impossible to play as written in the MM.
The damage resistance to weapons + regen would make them really hard to kill in the Underdark, but sunlight hypersensitivity would make them unplayably weak overland. Players would be screaming blue murder if all this were implemented.
Unlike other undead vampires have metabolism; poisons and potions work just fine on them.
Basically Astarion loses:
- Necrotic resistance
- normal weapon resistance
- Sunlight hypersensitivity
- Running water weakness
- Needing residence invite
- Spiderclimbing, and
- Feral nature
He retains his bite and stake vulnerability, plus unlike most spawn he's not not even close to feral, despite his master's mistreatment.
