> Genuinely curious - what do people want to see from a new/different rendering engine?
It should be fast when rendering HTML/CSS. I don't really care about JavaScript performance, because where possible I switch it off anyways.
It should be customizable and configurable, more than Firefox was before Electrolysis and certainly much more than Chrome.
It should support addons that can change, override, mangle, basically do everything imaginable to site content. But with configurable permissions per site.
It should support saving the current state of a website including the exact rendering at that moment for archiving. It should also support annotations (like comments, emphasis, corrections) for that. And it should support diffs for those saved states.
And if you include "the browser" in that:
I want a properly usable bookmarks manager, not the crap that current browsers have. Every bookmark should include (optionally, but easily) the exact page state at the time of bookmarking. Same for history.
Sync everything to a configurable git repo: config, bookmarks, history, open windows/tabs, annotations and saved website snapshots.
I want easily usable mass operations, like "save me every PDF from this tab group", "save all the pictures and name them sometopic-somewebsite-date-id.jpg" or "print all tabs that started with this search and all sites visited from there as PDF printouts into the documentation folder".
I want the ability to watch a website for changes, so the browser visits in the background and notifies me if anything relevant is different (this could be a really hard thing to get right I guess...).
I want "network perspectives" (for lack of a better word): show me this website as it would look from my local address, over this VPN, with my language set to Portuguese, ..., easily switchable per tab.
I want completely configurable keybindings for everything, like vimperator, but also for the bookmark manager, settings, really everything.
And I want a pony ;)