Holloway's 110H PR was run into a -1.7 headwind, which suggests along with his recent 60H PR that he can threaten 13.1 or so this year. At the same time, Holloway has split 44.10 indoors in the 4x4 and could probably run under 45 if he ran the open 400. He has about half a meter of improvement left in the long jump at the very least but is still consistently jumping over 8m/26'. He is nonetheless already competing at a level that could get him into multiple Olympic finals.
Seems like he has potential to be a unique athlete on the international stage. Ashton Eaton could have been world class in the hurdles, sprints, and long jump his whole career without ever picking up the decathlon, but Holloway should be able to pursue such a triple more successfully than Eaton could have.
I imagine in the next four years he will perform somewhere along these lines:
60H: 7.35
110H: 13.15
400: 44.60
LJ: 8.40 (27' mid)
He will contend for Olympic gold in the long jump and hurdles, and if he can make it onto the U.S 4x4 in Tokyo, that's a guaranteed gold. Later on, he might go down as the GOAT.