Why it is so easy to towerdive?
At late game, there should be absolutely no problem with towerdiving. After all, you are there to protect the towers during the late game; not the other way around, and people usually have enough tankyness to whitstand tower shots.
However, the real problem is during the early game. Towers are completely useless. A champion, no matter how squishy it is, can just dive with ease and still survive because a tower's damage is pathetic. Also because there are thousands of ways to drop tower aggro with the mobility creep.
There were times this week, on games, that champions were able to towerdive me without any punishment and still get alive... without any complete tanky items yet.