SD-WAN is an overlay and therefore has less need for coordination between vendors. Only time will tell to what extent the specifications created by the MEF will be adopted by the industry. The main concern of SPs and enterprises is the closed end-to-end nature of SD-WAN solutions and the vendor lock resulting from it.
Standards are made to make things work together but must also be tied to the business interests. Standards can’t force companies or users to accept them, they need to bring value. Many standards failed because they missed this point. SD-WAN standards are still under construction. What’s going to be their focus and fate?