I've tried Voyage, but it sacrifices too many features to compete with Amethyst.

I bet you could tie more performance improvements into the low-data mode and let people opt-in to it. I don't use the DMs, for instance. The once per day, that I check them, I can manually trigger the fetch.

I actually bought a new phone, just to use Amethyst, and then I got crushed by spotty mobile Internet. Tighter integration with Citrine and automatic network diagnosis could potentially make moving in and out of the connections seamless.