Very cool stuff! Have you considered making a mod?
First two ideas are great and have added them to the “to do”.
I feel like a larger land mass would be far too easy in terms of survival. I think most people would prefer the island survival setting, but again, I have no problem with a mod if some people prefer this as well. As for Perlin Noise itself, I’ve found it very slow in JavaScript. The Midpoint displacement algorithm I am using has always been leaps and bound faster than any Perlin Noise i’ve tried – but maybe I can revisit that if that isn’t the case anymore.