I remember in cata and MoP that Templar's Verdict hit like a truck. Not really sure how it compares now. At least it does more damage than Hammer of Wrath (lol). However when talking about finishers in a combo system at least they removed spells like Inquisition and made combo points on the rogue rather than the target to make target swapping easier.
IMO DP is the perfect finisher due to how it can interact with certain spells when talented with Insanity. It feels great to be able to empower your own abilities while building something up. On the flip side it sometimes feels terrible to have periods of meh DPS then periods of BOOM DPS.