There's no easy way to go back or forward in time in chunks bigger than key frames that is centered at current time/frame.
This can be done via dragging playback timeline cursor, but here comes inconvenient side effect - it's impossible to click on timeline cursor without jumping current video frame to something else. Understandably it's a feature for moving cursor somewhere else entirely, but if the click points to time within interval around current time (especially when it's a drag event start) it should assume that the click is done on exact current time and change video frame only on drag, which also should be calculated assuming that drag motion started at current time on timeline. This way you'll have a convenient way to move around current time.
Scrolling via frames (which is now on mouse wheel) is great, but this will give a stronger scroll which doesn't jump around at the beginning of the action.
