Take a Saganami-C. Now remove the armor. What do you have? A light cruiser (a heavy cruiser is armored, a light cruiser isn't; CLs have broadside grasers, DDs don't). Maybe take a missile tube and a graser out of each broadside to make it a little smaller. Admittedly, it's f*cking huge by CL standards, but it's still functionally a CL. Let's call it the Atticus.

What does the Atticus give you? Well it's much faster for a start - lower mass means a higher accel given the same compensator. But maybe you don't need all that extra accel, so you can put some of that removed mass back in as other things. Like extra life support so you can carry a larger marine complement (say TWO companies vs the Sag-C's one).
So now what do you have? What you have is an MDM equivalent of the classic CL - a reasonable endurance, fast but unarmored ship with an excellent marine complement (basically a short battalion) that is perfect for anti-piracy and commerce raiding work. And, when your enemies don't have MDMs and thus don't have the range to hit you, it's actually a more flexible (but less powerful) "space superiority platform" than a Sag-C.
IMHO, the "Atticus" is a better light ship than the Roland DD. The Roland is awesome, but it runs dry fast and it has NO marine complement. That makes it a terribly inflexible platform that really isn't suited to anti-piracy work and also runs into trouble if its task actually requires boots on the ground (cough-Saltash-cough). An Atticus fixes these problems.
So, why am I wrong?