And no it doesn't have to proc holy power if it becomes a viable proc FREE finisher. a "slightly stronger CS" is not compelling
Getting the bonus I suggested is the groundwork towards giving us some viable cleave aoe and with the proc rate you should have DS every 12ish seconds. It specifically lays the groundwork for potentially having DS redesigned <again> next expansion.
AlsoMy procs which are pretty frequent AND FREE on the same GCD make it hit for 450-700k crits varied on procs sometimes peaking mid 800's. Let's not even talk ab out the mastery damage.~80k -- that's over 70% of a TV
Currently the proc increases TV's damage by 120% OVERALL you say DS is 70% a TV. That's nearly half AND costs an attack GCD AND it's ever 3-4 seconds at 25% proc chance VS 40% chance 1-2times PER 3-4 seoncds.
From my dark animus last week which is a fairly average proc rate i got 26 HOLY templars verdicts. My holy NON crit TVs beat the AVERAGE damage of my HoW crits. Lets not even get into mastery scaling here.
Keep in mind the final weapon if it's not a legendary in T16 is going to have be 570 ilvl which should be pushing very close to 40k Top end weapon damage. Not to mention further mastery / haste scaling if we are lucky and the tier is filled with these stats. IF we do see epic gems this tier it FURTHER boosts the power of the current 4 set yet again. The holy TV is just too fucking powerful and too frequent.
DS in it's current form is shit. My suggestion is the ONLY viable solution to the set without going overboard and maintaining DS as the actual set bonus.