I think ground work can help emmensely, in some situations; you are able to get her feet to move, and to get her attention fully on you, without the concern of getting thrown, or having her react in any other way that could get you hurt from above.
I will normally do a brief 'mental' check of any horse I ride, especially if I am unfamiliar with it...I just do a little bit of lunging, hip and shoulder yielding, and some backing up. Just enough to make sure the horse is focused on me...I don't think ground work is ever a bad thing to do, even with a seasoned horse, as it is an easy way to prepare yourself for the ride itself, and helps you make sure the horse is paying attention to you, and not everything else around him. It is also an easy way to keep their ground manners, themselves, in check. It doesn't have to be alot of work, and actually I wouldn't want to see someone with a fairly seasoned horse, out there for hours on end "just" doing ground work...make sure there is a reason for it, and keep it as brief as it needs to be. If he needs it, fine, but don't carry it out forever.
"The ideal horseman has the courage of a lion, the patience of a saint, and the hands of a woman..."