I tend to prefer zoom in / out to the location indicated via the mouse pointer (a la Inkscape) but I understand. Because click-n-drag is used for rectangle marquee selection it would likely be a modified variant (e.g., CTRL+click-n-drag or similar) that would be used for this action. The current method is to use the scroll wheel (vertical position) and SHIFT + scroll wheel (horizontal position).
Enhancement request fdo#54469 appears to have been raised with Writer in mind, although the component is set to UI, so probably relates effectively to most components. The request there is to use the middle mouse button, but this will no doubt be determined by the Design / UX-advise teams.