“In plaintiffs' action against an energy company for aiding and abetting alleged breaches of fiduciary duty by the officers of a pipeline company, the court granted a motion in limine to exclude an expert's report under Del. R. Evid. 702(a) because it expressed a legal opinion on whether the fiduciaries' conduct was reasonable. [Also], [t]he expert report impermissibly expressed opinions about state of mind, which were factual determinations for the court to make. [Finally] [t]he expert offered impermissible opinions about whether the parties believed their agreement was breached, because he interpreted the agreement using extrinsic evidence.”