So you are thinking of Pricing for code access as a one time fee or a subscription ?
I think the biggest problem you guys got was the expectation of your customers. Since everybody had his personal expectations, you had a plan. But the plan was not the same as the expectations. So a subscription meant for the customers, hope to have their expectations fulfilled. This did not happen and therefor most people were unsatisfied. Why go again the same way?
Example with subscription as it is now:
12/11/16 today: The app contains no extended search function, I buy it for 399$ including 6 months subsciption and of course I hope to get the search done within my subscription and will be disappointed if this is not going to happen.
Better way to solve this:
You sell the app as it is now for 149$, everybody can see the included functions and options in the demo. I know what I will get and what I will not get. Nothing to hope for but nothing to be disappointed of. No subscription and no support beyond making the app work at the beginning. When time comes by and you are done with the extended search, I can think about buying the new version as it is then.
149$ might be way easier for many people to purchase the app, you are no longer under pressure to fulfill people's need in time of their subscription and you will save a lot of time due to the not existing support beyond the first configuration to make the app work for the customer. Talking about ES app only, no EB. I would suggest 199$ incl. EB but at last you got the decision to made as the developer of course.
Additionally a budget app, containing only stream, comments, commenting, profiles and private messages would be the least people need to have an app when running ES and this is already there inside the app. So this should be easy for you to make and when people got this app and you go on with features, one day they want more and will buy the latest app with more functions.
Best thing is, maybe you get less money per purchase, but probably more people will purchase the app so I just think there would be more money seeing this as a whole thing and, the most important aspect, people can not be unsatisfied about getting what they bought!
Result = Win/Win