I too would like to see an option for a menu bar. I think the use of a menu bar is a customer choice. People who are not involved in the debate are simply trying to browse the Internet. They are only looking for the easiest way to accomplish there tasks. The average Internet "user" is more interested in social networking or shopping or their average daily lives then a discussion of pixel counts.
The visionaries, that is us, are always pushing to go just a bit farther. The number of experiments that succeed are but a tiny fraction of all of them.
It's clear from this thread, people are still vested in a legacy menu-bar. If you want to remove the menu-bar, the simplest way is to provide an experiment that some number of people choose to Opt-In. It would then be obvious to the uninvolved to Opt-In to the experiment. Soon most will make the change and the issue is resolved by a vote of the customers.
The legacy desire could be satisfied using themes or customization of a theme. It appears that the effort to provide more theme development features has not been part of the thread's discussion. It could be that more Opera SDK options could yield unexpected benefits.
Firefox and Chrome are working very hard to turn browsers into applications engines. Much has been done already. I see that there is much more to do to make that idea happen. An example is the Mozilla Rust language or Google's DART. These are sign posts on the road to distributed application concurrency, security, and reliability.
Note the market for applications is huge. No single browser will own the application space. How can Opera Next be adapted to many possibilities?
John S Wolter