If I may be so bold, I'd like to make a suggestion in the area of armament.
As a runabout in the service of the Marine Corps, it's upped power production (over shuttles and other runabouts) should go mostly to increased shields and engine power for the purposes of insertion/extraction operations as opposed to increased energy weapon armament.
In the area of weapons, a single forward standard micro-torpedo launcher (common to the Danube and other shuttles) capable of handling both micro-photons and micro-quantums would work rather well with a possible rear launcher for good measure. Phasers could be pulse or beam with me personally having two forward/side emitters and two aft/rear-quarter emitters. This would give it adequate coverage in most all directions against small aggressors such as shuttles and fighters and even some larger patrol craft while still keeping it nimble enough to avoid most incoming fire. Of course some shield and engine power could be sacrificed to power scientific equipment should that become another purpose of this class of runabout (even the Defiant performed scientific and exploration missions despite it being categorized as a "warship" in it's own right). An external rollbar reminiscent of the Danube could also be possible to prevent from having to re-configure the interior too much to accomodate added sensors.
Just my 2 cents.
