Oh, they're will be MW5. The Mechwarrior consistently sold well throughtout it's history. MW4 sold over 500,000 units. But with the Mech Paks and Mercs and Mechassault, after Black Knight, Vengence, and MC2, the niche market was pretty heavily saturated, so they cancelled MW5. But in the ruthless and cutthroat business of gaming, a consisent seller is one of most valued things there is. After the appite has time to grow hungry they'll start on MW5.
And I agree MW4/BK singleplayer sucked. Somewhat odd too, considering the MW3/MC/MA series had good singleplayer. Great multiplayer though. Spent many thousand of hours online with it.
And oh, I suggest a little patience for a response at DSC. Might be a little while for the lurkers to rotate by and check the site.