One other feature that I am feeling the need for within 1 week of switching to vivaldi is that there should be some way to expand a tile to maxium-width i.e, shrinking all other tiles to their respective sides and maximum this particular tile and when the maximization is done, it should revert back to the original size and configuration.
Only one tile will be expandable at a time to maximum possible size.
My use case: When I get email, I mostly just read them in a 2-3 horizontal tile layout and give short replies. But sometimes when a proper reply is required, there is not enough space to compose one. So, I have to untile it and this just destroys all my custom-made tiling layout (which sadly can't be saved in current vivaldi versions) .
It can also be implemented as a tile-bar for each tile (this can be floating, removable and dockable). The tile-bar can contain all kinds of stuff like moving a tile to neighbouring spot, swapping with a neighbouring tile, address url, reload button, and most importantly expand this tile