New2grammar I feel you're describing the meaning of adhoc.
I don't think so. You could come upon a fence in a pasture and have no idea of it's purpose or the circumstances under which it was built, or how long it's been standing. Yet, knowing something about fences, you're able to judge that it was improvised.*****
Since I had previously opened the door to looking at the circumstances of why something may be improvised, I thought it should be clarified (that is, perhaps not always on the cheap).
Actually, "makeshift" and "improvised" speak more to the nature of the thing than to the circumstances under which it was created, even though the words themselves reference it's illegitimacy.
If I understand "ad hoc," it could apply to the most elegant, expensive, and carefully conceived temporary stage for a political debate.
On the other hand, you could argue that "ad hoc" applies to the stage as representative of the whole picture - both the special purpose, and the special circumstances under which it had to be improvised.
I hope someone more comfortable with the use of "ad hoc" can say if it applies here.
***** Note that we can say "was improvised" emphasizing the process, or "is improvised" emphasizing the quality.