I think whether Assad stays up after Hughes is healthy is going to be a sign of how much of this was by design or more of a "these are the guys we have, might as well use them" deal. Fulmer is definitely the most surprising. It'll be really interesting to see how often he does what he did yesterday.
It does have a lot of benefits though. You touched on guys being much less likely to pitch back-to-backs, which I'd guess is #1 by a pretty wide margin. Days in a row for a reliever is akin to times through the order for a starter.
And then yeah, Smyly and Steele were '5 and Dive' types last year. Smyly's far enough into his career that we know it's permanent. There's hope for Steele, but still the safe thing is to assume that'll continue for him as well. Wesneski probably has a pitch mix to not be limited in that way, but only time will tell. But 5 IP from the starter, 2-3 from a complimentary longman, and then hand it off to your late inning guys for the save is likely a good formula.
I wish we had a lefty who could do this too. Maybe Elias could be that guy? I'd give everyone a few more turns through the rotation, make sure we're past the early season injury danger zone, and then start using him this way down at Iowa.