Good thing we have better solutions than simply increasing the blocksize. The blocksize limit is already inspiring innovation to increase capacity without costly tradeoffs and we haven't even seen a fee market event occur yet....
have you actually looked at the data..
signatures =70bytes
changing the flags and other stuff add bytes.. changing the OP_return from 40 to 80 bytes to allow confidential payments.. adds bytes..
thats just 2 examples of the multitude of things that are going to add bytes to the main block.
so dont expect larger capacity for long.. by the time people have seen segwit running for a few months to trust it has no bugs. and then update their clients.. the new features would have bloated up any saving the signatures would have made.
segwit is not a capacity increase. its a diversion of data to allow for more features..