Hey, Mk2 D is a very decent mech. In fact, it is among my favourite assaults (along with Awesome D and Mauler D). CERLBLs provide some initial punch and are very universal. ATMs rape things on med range, allow to shoot without lock-on. And those HSLs comewhat compensate for the inability to use ATMs in close. They are real life-savers in some cases. Thre is a trick that allow to use both ATMs and HSLs in close - just double-jump back.