Do you think the half-tank champions` burst is too high?

Jax is not bad at laning phase, and good at split pushing and team fight. He can be tanky with high burst. But I feel like Jax`s strategy is fine. Those new items with HP, armor and damage damage this game. I had a game with about 15 kills ahead in 30 minites, everyone had the least 1 big item ahead and their Jax and Xin were like 4/8 or something like that. But they can 1 on 1 anyone easily. Also, the speed of split push is too fast. I do know we need to punish them somehow when they split push, but if some champions can kill tower in 7 seconds and kill squishy champion in 3 seconds and also tank tons of damage! There is not really much we can do. For example, Lee and Udyr are strong in some point even in those days without new items, you need to learn how to dance among people, I like to play against champions like that. But now, you can build the tanky and damaging items on champions like Xin, you just jump in and roll your face on keyboard. I am low level players, but I do miss the days when our champions are classified as assassin, tank, early game champion and late game champion and Maphite is good against heavy AD team. Now, you may already know, Maphite operates very well even against a team with 2 AP.

In one word, need to fix whatever it is to make some champions with no weakness and destroy the team fight by simply jumping in, dealing tons of damage and tanking everything.