Now that Avi is gone, the outfield is the place where the biggest hole should be filled. None of the youngsters are ready except Eloy. So, Eloy in one of the corners and, depending upon the defense of the anticipated acquisition, maybe Engel, or Leury in CF. For me, Harper checks the most boxes. He would fill the other corner OF slot, and provide the much needed LH bat. Without a big bat taking Avi's place, the outfield would be pretty weak, offensively, with only Eloy as a potentially big producer. To have cleared Avi from the roster, only to replace him with Delmonico or Palka, makes little sense. Palka deserves more opportunities, but not in the outfield. He should be destined for either DH or first base.
I still think that Moncada should be given 2019 to adjust to his anticipated future position of third base, to open second for Madrigal, which seems to be the only really good spot for him, hopefully in 2020. Yolmer would be an acceptable "place holder" at the keystone spot, until Madrigal is ready.
Add to those factors, the better star power and "character" of Harper, and for me, it's not even close. I still don't want Machado to be the "face of the franchise," for reasons I've expressed before and which many of you share.