Banshees are esentials the most useless caster in the game. all other casters have amazing initiate spells, like fairie fire, spirit link, purge, sentry wards, roar, raise dead, heal and slow. wow curse is a spell that pretty much relies on luck.
Anti-magic shell is worthless. it blocks out 300 magic damage. That is next to useless, since almost all spell damage has a secondsary effect to it which AMS ignores, caster attacks does to little to wast 75 mana, and flying units do to much damage for it to be effective. useless
Possession is useless. anyone with half a brain can see and kill the banshee. the cast time is way to long, and the range is way to short. and they receive 166% extra damage? all units kill it in like 2 shots without that multiplier. its ludacris and the banshee is so expensiive for the useless spells.