1) Rabbi Kanievsky is not the Litvish equivalent of the Rebbe. America has its own poskim.
2) Are you suggesting this is a bad thing to have kavana while davening? I don’t see your point.
3) We’re at the mercy of what the yeshivos decide to do. Most American yeshivas (not all) tend to follow some variation of the Slabodka derech halimud. Nonetheless, most places have both a seder b’iyun and b’kius. Are you suggesting people should do away in learning b’iyun altogether?
4) Not without controversy even within the Litvish community. Many if not most Yeshivos don’t do this, but it’s popular in Chofetz Chaim communities which is what many people see.
“i know some will answer, that thats “our minhag/ mesora”, ok so why do you guys criticize chabad”
Because Ashkenaz and Sphard are real mesoras based on poskim of previous generations. Chabad is an invented mesora based on hashkafa and the whims of its Rebbes. I know you were probably baiting one of us to say this, but why shouldn’t we? It’s just the historical reality.