I dislike the main menu button and context. I would like to see you to implement an ability to move it to the right of the address bar just like Chromes. I would really appreciate this feature.
What I would like to see regarding the menu button is either 1) They take out the red background and let it be just a white V so there's no red to clash against non-red websites, and/or 2) The red background of the icon actually changing colors with the color of the website. These would be great, and even an option would be nice. This would put Vivaldi ahead of every browser 100% in aesthetics in my book.
And yes, it would be great to move menu buttons and other buttons around. I do know that the Vivaldi team has acknowledged that they will do this, and it is their goal to implement moving buttons around in the browser and removing buttons as the user wishes. It will come, probably not in the stable release, but it will come.