First of all, fantastic project. By far the best micro ROV i have seen so far.
Having the ability to fly the rov lateral is absolutely necessery. Especially in a situation where you have bad visibility, soft seabed or inside a wreck. Having the possibility to fix the camera on a fixed spot and move around it combinding lat/fwd/aft and spin is very important.
Vertrans thruster config works best on a round vessel, like a ball (ex: HyBall http://188.8.131.52/hyball.html ) or a tube shaped hull. The use of a lateral thruster through the belly of the ROV is the simplyest way of doing it and would work best with the over all design of the OpenRov.
Adding a panning camera is not the way to go. The reason observation class rov's don't have it is because it dosent realy work. The only practical way of manuvering a camera is with lateral and axial thrust, and spin of course. Pannning cameras is mostly only used on work class rov's for manipulator operations.