A strong malleability fix _requires_ segregation of signatures.
No, none of the alleged benefits of SegWit requires segregation of signatures:
* Malleability could be fixed by just skipping the signatures (the same data that SegWit would segregate) when computing the txid.
* GREATER bandwidth savings could be obtained by providing API/RPC calls that simple clients can use to fetch the data that they need from full nodes, sans the signatures etc. This enhancement would not even be a soft fork, and would let simple clients save bandwidth even when fetching legacy (non-SegWit) blocks and transactions.
* Pruning signature data from old transactions can be done the same way.
* Increasing the network capacity can be achieved by increasing the block size limit, of course.
It seems to me many people have a problem with segwit because of the "hackish" softfork and/or because of the change of the economic model (2 classes of blockspace).
If we did the points listed by JorgeStolfi above as a hardfork, would that be an option for the proponents of segwit? Seems to me such a hardfork could gain wide consensus, maybe wide enough to be considered safe by everyone? It would certainly appeal to the people who just want a simple blocksize increase and it
should (I don't know, though) also satisfy the people who want segwit now.
What would be missing compared to segwit? fraud proofs? change of economic model?
Yeah, both hackish (although possibly beautiful code) and the economic model, if I understand that correctly.
I don't think segwit could ever achieve HF consensus, my opinion. However if a winning hard fork was achieved, I would respect that.
A soft fork is not right here, and could well be considered an attack.
Why not 2mb first, which is on every partisan roadmap. Then segwit maybe. maybe not.
(I am assuming 2mb is more easily coded than segwit, and not as complicated as segwit as was stated earlier. Although the ease of coding is only a small part of the reason segwit should not be introduced yet. certainly not introduced by core. a SF attack on nodes.)