If the UI layer depends on the engine it probably takes as long to port it to a new engine as it does to just do it from scratch (or maybe even longer because of all the bugs that would inevitably appear because of the old Opera’s crazy complexity of settings and features).
You’re complaining about Opera 15 as if it’s the end of the line but in reality it’s just the start. Complain when they’ve had more time to do stuff.
