Two prominent Bitcoin Core contributors, Jeff Garzik and Gavin Andressen, co-wrote a response to the recently published bitcoin scalability roadmap by Gregory Maxwell, which is based on the SegWit concept.

While recognizing that there are some great ideas involved in the roadmap, Garzik and Andressen state that the whole idea completely ignores such important issues as possible growth of fees in case it is implemented.

http://forklog.net/garzik-and-andressen-state-that-maxwells-bitcoin-roadmap-lacks-consideration-of-important-issues/