I would argue that the only reasons for larger tires (besides looks) are:
Primarily:
Ground Clearance and rolling resistance for obstacles (the larger the tire the easier it is to go over larger obstacles due to the larger diameter).
Secondarily:
The larger the tire, the heavier the tire, there for the Lower the CG of the vehicle.
entry/departure angle, break over angle, all have more to do with lift height. Not to say they do not change with tire size, but they are more related to total lift than tires specifically.
Michael