... or use a "commercial crew" vehicle mission to dock and be a "hot standby"?
Unless you are suggesting a commercial crew vehicle transfer crew to-from ISS, then to to-from Orion, so that Orion does not have to dock to ISS?
Yes. Can be worked into ISS schedules/missions.
Also has additional safety advantages for if stuck thruster, can chase down disabled SC. And more if you think about it.
You also can use it as a logistics support capability to extend CRS into exploration missions, with a demo of resupply.
add:
So here's the mission profile - crew from launched Dragon/Starliner (or ISS) actively dock with a passively stabilized, holding station Orion launched using the same Delta IV Heavy with same payload adapter as before, no launch abort tower (weight) or LV HR mods (as before). You'd really want though to test a full up ESM (number 2 or 3?), which would depend on unproven Delta IV Heavy payload capacity (no one's ever used the solids on Heavy yet, but there's no reason to think it's untenable, and it would allow ULA to hold on to the heavy lift title in commercial launch for another half decade or so, and you'd only need 2 of them). For ESM it would alter payload processing and need to shift the umbilical's on the tower (it's taller), and some changes to the payload adapter.
Advantage of this also would be to have a means to develop/operate Orion w/o SLS being in lockstep as each becomes the other's "long pole", which has played into the post Shuttle HSF dilemma the entire time.
Resistance to this, like with EFT-1 and CC, is ... useless. The lack of such capability in the program means that a) you can't advance it rapidly, and b) you have joke missions for the costly and (for the joke missions) over qualified vehicles (Orion and SLS) instead of something worth the caliber of those vehicles as intended.