Transaction encoding can give 20-30% disk space and reduction of bandwidth. Good, but not good enough.
New signatures need SegWit anyway:
So the way we could use this to improve scalability in Bitcoin would be to add a OP_GROUPCHECKSIGVERIFY (and perhaps a multi-version of it) as part of a new segwit
script typecode that takes as input sighash flags and a pubkey.
It can give additional 40% capacity and can raise security. Good, but still not enough to scale.
So we can doube-triple current tps? We will need like 100x and more. This can help, but it is not a remedy on 10x or 50x more transactions we have now.
I`m not supporting scaling by raise block size to the moon, we just need more space
now. Raising block size
and adapting segwit in same time give us much more space and open new possibilities that segwit give us. But it all need TIME. And we run out of it, like 6 months ago.
So, raise block to 2MB is bare minimum we need. Segwit is must-have. We need both.