the delay on sennas stun effect is low key op

it's a really strong part of kits like zoe and fizz as it gives them a really long time for them and allies to set up a good follow up, but sennas is big aoe stun on basic ability.

on top of her crazy aoe ranged damage and heals, I honestly didn't realize how effective the application of her stun was til now(average senna skill level progressively increased)