Tying any single target damage increase to only one of our level 90 talents would just cause problems. Especially since DS is not even the optimal single target choice, it's just better for fights where we can't get to range. Hopefully blizz can come up with something to increase our stat weights slightly so that any buff won't have to be repeated if we fall behind in scaling.
Divine star is completely boss right now, I find myself taking it on a lot of fights now that it got buffed a month or so ago. I like where the talent is damage wise right now, better than halo when you're not at max range. As long as next tier has a mix of fights that keep us close and far away there will be no reason to change the way it works or its numbers.