The UK has little choice but to remain with EASA. The loss of voting rights is hardly helpful - I believe voting rights are proportional to the size of a country's industry, so Germany and France will rule the roost. That said, they already do to a large extent, with EASA's HQ in Cologne and a succession of French nationals running the Agency.
However, EASA has a dearth of expertise and the UK has been instrumental in sorting out a lot of the mess that the Agency has created, and I can't see them turning away our free expertise in future.
What is of greater concern is the bulk adoption of EU law into UK law. If the timing isn't right then it will mean that the UK will inherit a collection of current aviation laws that aren't fit for purpose, which EASA are currently looking to change at their usual glacial rate.
However, I believe that there are more differences filed with ICAO than there are standards, so plus ca change as we commence roll-out of a million Alternative Means of Compliance (AltMCs) to EASA diktats.