i think caitlyn is fine. shes my main adc. people have a lot of thoughts about her that are jsut simply false. and ppl have ideas about what the only good adc are which is also simply false. her kit is great and works as intended. an adc should not do damage from abilities late game its all about autoattacks. their last buff was good because she does struggle a bit with mana in early and mid game. People jsut dont play her well thats the only issue i see...they seem to think she is a weak jinx or something...if you try to play her like jinx then it wont work.
her ult works fine. frankly i use it most often when im split pushing and some assasin decides they can 1v1 one and quickly discover they cant...so when they try to run away thats when i ult. in teamfights, you need to know the good positions for cait...for example behind walls is good. for example if your team is fighting for the 2nd bottom tower, you can hang out around the golems. ppl would have a hard time reaching you if you place a trap in the right place, u can e over the wall if needed, you get a bonus if you shoot from brush, and its harder for ppl to block your ult when they dont see you and are sideways. the ult doesnt need to kill people, just chunk them so they cant do what they want....soraka is a good target for example, or a bruiser who wont feel able to engage if his life is low, things like that. theres no actual rule that states u have to ult people who are nearly dead.