We can't patch Firefox without getting approval from Mozilla and still call it Firefox, due to trademark guidelines and such.
If we don't want to theme Firefox properly... Epiphany works great for
me. :)You are biased, as you said before. Epiphany still has rendering problems in many websites, it doesn't support privacy-enhancing extensions such as privacy badger and HTTPS Everywhere, it doens't support custom adblocking lists (the default adblocking list only works for global websites and not for local ad networks in my country, for example!), it doesn't support many newer web platform APIs, doesn't have a sync solution... the list goes on and on.