I agree with you 100%. You make some very good points.
"Unfortunately, descriptions I've seen only talk about . . . the cow hitch coming apart easily if you don't tension both ends coming off the object. So, I never really gave the cow hitch much thought."
I agree: Strictly as a hitch, it's utterly horrible; but, when used in tandem with an end loop, it's incredibly useful and wonderfully fast and simple. Often, in knotting, the simplest structures have the greatest value.
"For a cow hitch/fixed loop combination, tie a bowline loop . . ."
I like that one myself. If you like that method, then you might like this one, too, as it offers a couple of extra benefits: Try a Bowstring Loop (a.k.a. Honda Knot) and then hitch the loop to a post using a Cow-Hitch structure.
The Cow Hitch is the perfect companion to the Bowstring Loop. The Bowstring Knot is actually an unusual type of slide-and-grip knot. It holds spectacularly well--but only when the shape of the Bowstring Loop is elongated. The Cow Hitch guarantees that the Bowstring Loop will stay elongated and closed (also important to keep the Bowstring's tail from falling into its loop and being accidentally pulled once it's in there, which will convert the Bowstring Loop into nothing more than a working end going through the MIDDLE of an Overhand). This very quick-and-easy combination structure will give you perpetual adjustability: Say you want to suspend an object at a precise height, have a quick and easy way to do it, maintain quick-and-easy perpetual adjustability, and have the guarantee of no slippage. The Cow-Hitched Honda to the rescue!
My experiments with dental floss reveal that the Bowstring Knot slips a little--very little--but only in the context of many, hard, REPEATED TUGS, in such a way that the main problem is that it slightly damages the cord. The presence of a Cow Hitch solves this problem entirely and eliminates both the slippage and the damage to the cord.
". . . but that can be an advantage depending on the application . . ."
I love this statement. I am so glad to hear someone else confirm this thought that I hold to be true and so very important.
". . . relatively big profile . . ."
Want to reduce the profile and the amount of cord used? Try this: Make a Bowstring Loop, hitch it to a post using the Cow-Hitch structure, and then slowly pull the tail of the Bowstring Loop to reduce the size of the loop. Keep pulling until the loop gets so small that the Cow Hitch winds up passing the Bowstring Knot and going over the standing part (you'll need to help it along) and turning the whole structure into what I usually call a "Fixed-Loop-Based Hitch" (which most just call a "Running Loop"), which can be considered to be related to the Cow Hitch. This uses less cord, has a smaller profile, and is related to the Cow Hitch!
JCS