Why do we need big blocks again? Why do we need SegWit again?
Let's see how SegWit works for Litecoin first.
Litecoin is not a real test scenario, the traffic in litecoin is really small compared to bitcoin, so you can't extrapolate any useful data to apply on bitcoin as far as a I know.
In any case, it's obvious why we need segwit and lightning network (and increase blocksize to 2mb after we get segwit running)