1. I think we should limit the sum of the block and witness data to nBlockMaxSize*7/4 per block, for a maximum of 1.75 MB total. I don't like the idea that SegWit would give us 1.75 MB of capacity in the typical case, but we have to have hardware capable of 4 MB in adversarial conditions (i.e. intentional multisig). I think a limit to the segwit size allays that concern.

2. I think that segwit is a substantial change to how Bitcoin works, and I very strongly believe that we should not rush this. It changes the block structure, it changes the transaction structure, it changes the network protocol, it changes SPV wallet software, it changes block explorers, and it has changes that affect most other parts of the Bitcoin ecosystem. After we decide to implement it, and have a final version of the code that will be merged, we should give developers of other Bitcoin software time to implement code that supports the new transaction/witness formats.

When you guys say "as soon as possible," what do you mean exactly?

On Dec 10, 2015, at 2:47 PM, jl2012--- via bitcoin-dev <bitcoin-dev@lists.linuxfoundation.org> wrote:

> It seems the current consensus is to implement Segregated Witness. SW opens many new possibilities but we need a balance between new features and deployment time frame. I'm listing by my priority:
> 
> 1-2 are about scalability and have highest priority
> 
> 1. Witness size limit: with SW we should allow a bigger overall block size. It seems 2MB is considered to be safe for many people. However, the exact size and growth of block size should be determined based on testing and reasonable projection.
> 
> 2. Deployment time frame: I prefer as soon as possible, even if none of the following new features are implemented. This is not only a technical issue but also a response to the community which has been waiting for a scaling solution for years
>