The nightly tab interface is a lot better, with the tab close buttons on the right. Previously with the tab expander button in the top right and the close buttons on the left edge, closing tabs meant reaching all the way from one corner to the other side of the screen, which is not always easy or possible with a single finger.
I think you should definitely pursue tweaks that reduce the amount of finger movement required to do common tasks. Just to steal one example from Opera, when you long-press a link, the context menu appears directly under your fingers, so you don't have to go anywhere to get to it (similar to the right-click menu on the desktop). This is incredibly convenient, because navigating the context menu doesn't cause you to lose your place on the page.
I'm hoping for something like the stock browser's quick controls myself. I find them much easier to use quickly, and even a little bit of extra screen space is nice to have on a phone.
I think you should definitely pursue tweaks that reduce the amount of finger movement required to do common tasks. Just to steal one example from Opera, when you long-press a link, the context menu appears directly under your fingers, so you don't have to go anywhere to get to it (similar to the right-click menu on the desktop). This is incredibly convenient, because navigating the context menu doesn't cause you to lose your place on the page.