From my experience, I'd absolutely say replace that DMD.
When I had my Twister up for sale, with a detailed description of the fuse-blowing issue it had (that I had spent a year-and-a-half and $700 on trying to fix), THE problem that all interested buyers seemed most concerned with was that the DMD had 5 vertical lines out on it.
Even had one guy tell me that he wasn't "worried" about the fuse issue because it was an "easy fix", but that the DMD was a deal-breaker, because replacing displays was "one of the more costly repairs that can be done to a pinball machine". I explained to him how that wasn't exactly the case, but he said his "repair guy" assured him otherwise.