Wentz is better than Elder, imo. I would much rather give him starts than Elder.
Not to mention, even before our off-season moves, we already have a starting 5, with Lopez and Waldrep as our 4 and 5 pitchers. We also have Holmes who should be ready to start the season and could start a handful of games if needed. JR Ritchie is ML ready. Fuentes is basically ready as well. We also have guys like Hackenberg, Braun, and Burkhalter who are all in AAA, who all have back end of the rotation potential.
I am sure Elder will be back, because he is pre-arb. But I wouldn't even waste a 40 man roster spot on him personally.