Edit: got to it via google cache, looks like it's just based on chromium, didn't check to see if it had more JavaScript in it though as it didn't do anything to interest me.

I'd love to see a completely newly written browser in Go, C or Swift that is written from the ground up with security and privacy as it's key concern followed by speed. It'd need to be quite modular by design so that security components could easily be upgraded over time and so that new web technologies could be added as they appear. Multi-process, addon (if any) sand boxing and local to-a-directory synchronisation would be wonderful.