As much as I'd rather see jobs that could build towards multiple roles
within their actual rotations or be allotting their uptime and tools to those purposes (not just in how often they're healing vs. dpsing, but also in preparation, resources built, combos variably finished, and CD usage, etc.), even jobs that can fulfill multiple roles by swapping outside of duty or by changing role gear sets between pulls, etc., could probably help a lot.
Ideally, I'd want most jobs to have a larger level of accessible, but not necessarily immediate, options available to them (they can heal, but it has a skill ceiling to weave in such as to not cripple one's dps alongside it; limited off-role burst, filler, or immediacy), that make you feel more like the "job" rather than the "role".
That's mostly just my preferences talking for now though. I'd take a long essay to establish why I think that'd help so much with the future of the game in the long run.
Also, a whole hog iteration of DRK dps could and should be terrifying. Fewer tools automatically allotted exclusively towards mitigation, but even more able to use what mitigation they create for utter havoc...