We can add an option to export all data (in the pipeline) and let users delete account and data in one click (available on first release) but I don't know what else can be done.
End to end encryption is hard and I am not a programmer capable of implementing it safe enough to stop NSA level threats.
We will do what we can.
I don't think there's anything technical you can do. I think it would require:
1. A stable income stream that doesn't depend on something at odds with your goals (i.e. not like Mozilla).
2. Incorporate as a non-profit with rock-solid "we're never going to transition to for-profit" legal terms.
I think Wikipedia is probably the closest thing we have to that, but even they don't have a reliable income source. I mean, they have more money than they know what to do with and waste most of it on outreach nonsense rather than putting it into an endowment... but it's not exactly a reliable source of money.