Even though soft forking Bitcoin to implement Segregated Witness is the safer option compared to forcing a hard fork, there are still some unresolved issues regarding this proposal. Several changes would have to be made to Bitcoin’s source code at the core level, which could affect other features provided by the popular digital currency.
Keeping in mind how the transaction aspect of Bitcoin concerns companies, payment processors, miners, and exchanges, the development of Segregated Witness should not be rushed, but properly executed. Some people expect to see the Bitcoin Core upgrade completed by April of 2016, but that date may turn out to be very unrealistic.
http://www.newsbtc.com/2016/02/11/segregated-witness-will-not-block-bitcoin-development-needs/