UL gear by nature sacrifices a bit of durability to get the job done. UL gear will wear out a bit faster than non-UL gear. Example, packs: I have a 40 year old Tough Traveler, 2600CI pack. I use it every day on morning hikes. It weighs 2#2. I buy UL packs at 8oz to save 1#10. But these only last about 5-6 years. For the trade off in weight, I pay in cost (buy 6 packs instead of one.) I know they will eventually die, even if they get good maintenence.
Durability has little to do with reliability in the field. Whatever you decide to bring needs to be a bit more reliable, because, UL demands multi-use where possible.
Example: The older Impulse lights are great, but over a few trips the light seems to reduce from all the scratches on the lens. I can stand on it, dip it in water, it always works, but maybe not as well as it used too. I used to carry two lights (two old double AA lights) because I dropped one and watched it "explode" on some rocks. Bulb, lens cover, and case shed pieces. The little Impulse is far more reliable.
Repairability is another thing. If I puncture a Neoair in the field, I cannot repair it. There is a 100% failure. Locating a leak, patching it, and getting it to hold air are not things I can do easily, so I do not consider it field repairable. Example: Duct tape repirs to the bottom of the pack got me out after ripping the entire bottom out of the pack (I slipped down a steep slide in the ADK's tearing the bottoms out of both pouches and the pack after a rock step broke.) It worked well enough to complete the trip.
You might to spend more time with maintenence with UL gear. "I also had the stays actually go through the bottom of the pack where the stay holsters end." sounds like a good area for a heavy duty patch. While a bit of duct tape will get you out, OK, a more permanent repair can be made with a bit of sewing. Maybe you need a piece of strapping sewn in there? My overall philosophy on patching a pack is I do NOT want to have it fail *twice* in the same spot. Soo, my overall repairs tend to be heavier than the origonal. Example: The G5 had some stretching issues where the shoulder harness buckle was mounted on the shoulder strap. So, I added a piece of silnylon cloth on both straps after removing the buckle. I added a longer mounting strap and sewed the buckle on. It upped the weight about a half ounce, but I never worried the buckle/strap mount would fail again. Heavier than designed, but far easier than having them fail in the field.
Shoes are another area where I tend to stick with more durable, ultra reliable gear. I have tried many trail runners. I destroy them, somehow, in three to four weeks on the trail. My mid hikers, I have had for many years. Indeed the soles are nearly worn smooth after 7-8 years. I have far fewer problems, the soles have never delaminated, they remain water restant for deep puddles (2-3"), have soft rubber for gripping on rocks, a fairly stiff sole for walking on pointed rocks, and have a rubber toe cap for kick-stepping in snow. I have gone through 8 pr of trail runners, yet always go back to the mids every other trip.
Lately, Skurka has gotten the concept of "Stupid Light" across to most UL'ers. It sounds to me that if you must bring a trowel, you likely need another one that will take your usage. The one you have clearly does not if you have trouble using it.
Down jackets are real good as wind shells. But they *do* need cinches. A few years back, Eddie Bauer started to make good down sweaters and jackets... At around 12-13 ounce, they have several features you might be interested in.
Bags or Quilts...always the question. I tried quilts but found them to be less versitile than a bag. Mornings I unzip the bottom and walk around in my bag, for instance. The hood I like for keeping my head warm (uhh...balding head, I would add.)
I toss and turn a lot...with quilts, every toss and turn is accompanied by a blast of cold air. I could never get used to them. So after several tries, I went back to a bag.
As a comparison(using about a 32F system):
$385(Bag) + $30(NightLite pad) = ~415
$240(Quilt) + $150(Xtherm) + #30(balaclava) = ~420
1#11+10 = 2#5 (combined weight sleeping bag and pad)
1#1+15+2 = 2#2 (combined weight, quilt, better pad, balaclava)
It doesn't really matter when everything is evaluated in use. It all goes into the backpack, somewhere as weight.