Which support item is Janna going to take exactly?

ancient coint is being changed into a thresh passive, tell me what can janna build since her tornado is slow+costs 1/4 of her mana, she has 450 range unlike other ranged supports with clucky attacks, how can she builds ancient coin if enemies can deny her now? how can she build spellthief edge if she can't fight other mages that are going to destroy her if she tries to harass with attacks?

hopefully, those changes might make wake up riot and give her a better interaction in lane by buffing her auto attacks range