Vampire's bane and reflective light are both pretty good, but they has some problems, first of all it's the duration, the duration of vampire's bane is 11.7 seconds, and the duration of reflective light is 6.5 seconds, which means that you lose at least one tick of the dot damage thanks to this *** up duration.
Also on my tooltip reflective light deals 10.5 k dot damage, while vampire deal 17k, Not saying that this is bad, but the problem is that if you do a standard rotation with magplar, you will have to reapply vampire's bane when it still has't run out, which means you will lose dps, not to mention that reflective light hits max 3 targets, while vampire's bane only hits one, so it's only fair that vampire should deal more single target damage. My suggestion for this is to reduce the duration to exactly 10 seconds, and to keep the same damage.