I've noticed that even when tied in soft braided nylon, they tend not to draw up as smoothly as the Draw Knot. A bit more sequential adjustment of the individual lines is required.
The same thing happens in all Gleipnir-like binders. It simply has to do with the fact those binders use both wraps the way they use them, to utilize the offered mechanical advantage. The situation is different in the "handcuff-like" binders :
http://igkt.net/sm/index.php?topic=4821.msg31429#msg31429 So, there is no difference between the symmetric and the asymmetric Clove-hitch based binder you show - I have not seen any such difference, and I do not see the reason there should be any.
Perhaps I am tying more slippery cords over more slippery objects. .
No, I use some quite slippery caving/canyoning ropes, wrapped around the sleek PVC tubes shown in my pictures The only reason I can imagine, which may, I repeat, may cause some difference, is that I always use stiff, thick ropes ( 9-12.5mm ), not small size cords.
...different expectations as to how this kind of knot should operate,
...operate the knots under different conditions,
From the very first moment I saw the Gleipnir, I knew that, if we want to use one, only, nub ( i.e., without just adding a second Glepnir, as the author of the original Glepnir had suggested ), we should always use the friction between the two ends, by twisting them around each other into their surrounding nipping structure, in order to get a more secure knot, able to withstand a stronger pull. That is why a two- or even three-turns Gleipnir makes sense : the double or triple nipping loop is much longer, forms a longer "nipping tube", so the two Tail Ends have more/enough room to complete a turn around each other. Many people who just "watch" how knots are tied, but who do not tie them a sufficiently large number of times, do not have, to this day ( after 6 = six years ! ) understood the great difference in the holding power between a Gleipnir with "crossed" / twisted / embraced Tail Ends, and the "original" Gleipnir.
The Gleipnir-like binders can withstand more tension than it is believed/expected by the "average" knot user. However, when the most "popular" web site on knots does not even include the Gleipnir in the 337 (!) knots it "animates"

, we should not be surprized by this lack of understanding.
THAT is the reason I had never tied the asymmetric Clove-hitch-based Gleipnir binder you show in this thread, although I had tied and tried both the symmetric versions many times. Since the two ends, when they enter-into and exit-from the same side of the nipping Clove hitch, can not be dressed in an "elbow" configuration, and even if we manage to twist them around each other, this twist is not stable, and it does not remain intact during the later tensioning, I had dismissed the asymmetric case right beforehand.
When using slipperier cords the threshold at which the differentially tensioned lines will slip out is reduced,
Of course - but what will happen when the bound object(s) have sharp edges, as it often happens ? Even very slippery cords, when tensioned hard, do not slide easily around sharp corners.
I have a problem with the way you use the word "structure", and you have a problem with the way I use the word "design",
I do not use the word "structure" in any particular way, because I have designed and built things ( apartment buildings ) which have not, to this day, fell down

, and I know. My point was, simply, that "structure" is different from "form", as you said, or from "shape", or "pattern", or "geometry", or whatever word you use for something visible, that does not take into account the interaction between the materials and the various forces, which determines how a thing "works", why it does not fall down = why a knot does not fall apart.
Now, the "design" of objects is a very object-depended procedure. It is a different thing to design a boat ( I use this example on purpose, because there is a well-know description of the boat design as a "spiral" which. although very simplistic, nevertheless is interesting ), and a different thing to design a chair, or a bottle. The amount of resemblance of what the designer had in mind as a "purpose" or "form" for this object, before he concludes his design, and what the final object itself does, or how it looks, varies a lot. I only have this to say : In practical knots, there is no such resemblance whatsoever !

On the contrary, when one happens to find a practical knot that works, he is surprized by its looks, and even more by how it works and he may need some time before he understands why, on Earth, this knot works, while the knot he initially had in his mind does not ! So this is how I judge the greatness of a knot : Does it surprizes me ? The greater the knot, the bigger the surprize !
Am I surprized by the knot you show in this thread ? Nooope. Why ? Because I "see" the structure of a Gleipnir-like binder ( and I already know that a Gleipnir works, and how it works ), and I do not "see" anything else. Is it a "new" knot ? To me, although I had never seen it or tied it, it is not. To other knot tyers, using more strict criteria ( if it was published, in exactly this form, previously, etc ), may be. However, personally I do not care about "novelties", especially when they are skin-deep, i.e., novelties of one form/shape of one knot. I am interested about things, "old" or "new", that can teach something about the structure of knots, so someday we will become able to understand ALL knots. Does this knot "work" ? Of course it does - but as knot tyers ( and not knot-users, consumers of knots, advertisers of knots, sellers of knots, etc. ), I believe we are beyond the point when we were just interested in anything that works - perhaps because we know that any convoluted enough knot ''works" ?
Is that why I'm not having to individually adjust the tension in the lines?
If I remember correctly, the author of the Gleipnir used the original, single-nipping-loop-based binder to tie furniture he moved with his truck - and furniture ( at least not the "biomorphically" designed ones

) has sharp corners.
If the binder has not reached its limit, the difference in tension between segments of wraps or the wraps themselves may not matter much - but I do not like "structures"

where we do not have the most even distribution of forces possible : I imagine that, this way, we somehow help the future failure to be "focused" on one part of the whole, and that makes its job easier.