Poppy Questions

So I decided to try out poppy because she was cheap and I never seen her in game. I watched some vids read about her strengths and weaknesses and thought I would try her int he support role. My thought was this would help me earn gold during the poor laning phase and I could help poke enemies and turret dive and the like. I bring along some friends and had some success. Poppy was able to stun, and KaPwow things and the adc would finish off the champ. I built talisman and everyone gained movement which helps poppy.

Ok fast forward, I am away from my friends and I try poppy in different roles and even in support roles. I play poppy until I am rank 4 in poppy. I have an observation and I have some questions because frankly I am only slightly above average as a player so maybe I am simply doing something wrong.

Scenario We are just leaving the laning phase and as poppy I have say a trinity force built and maybe a second item. I see a full health adc alone under a turret with no creep wave and I have a couple creeps to back me up so I am thinking what a great opportunity to try and turret dive with my ult. I get close and I successfully E the sucker into her own turret for the stun. I follow this up with a Q and well not dead. I click R and I stop the turret from hitting me and the adc begins to run around her turret. I have a hard time getting off an auto attack and then her creep wave shows up stoping my movement as the ADC starts shooting me. Oh no my 6 seconds are up and the turret is pounding at me. I die.

My question is shouldn't poppy be able to kill an ADC with a couple hits considering she is suppose to be some kind of hyper carry or is the situation I described the reason why you don't see too many poppys?