I think it depends on whether you trust the Governors and believe they can do a good job. If they become an Academy they may sack the Head straight away anyway! (or not, if the Head is in support of the Academy status, and the Governors support the Head).
An Academy can run it's own Admissions and set criteria. Some have blatently set criteria which enable them to massage the catchment and manipulate the intake, and use this as a method to raise achievement statistics. (some do this by naming feeder schools, or admissions by lottery, or naming a geographical catchment, or introducing up to 15% of the intake on scholarships, for example). Have a look at a few local authorties schools on the Department for Education website where you can see the proportion of Free School meals for each school - many academies, foundation schools, faith schools and free schools have a lower ratio of FSM than other schools in the area - all these schools are able to set their own admissions criteria.
Academies can exclude kids at will, and set their own contractual terms for teachers..
You may or may not agree with or support these factors, but the Governors should be able to tell you exactly what they plan as an Academy, so that you can work out whether you support the idea or not.
Ask specific questions such as what would the admissions criteria be, would the policy on discipline and exclusion remain the same. Get all the answers to this minuted in a meeting between parents and governors.