They were at one time but I think the down side of them lead to their rapid drop off in popularity I think people got them used them then realized they were becoming carpet tanks. I would say it is a balance thing except with no bonus beyond +10 Dodge AC and +1 Attack per Round even if it is low level loot it is rather weak for most classes and builds and always have been. I see their once popular status more as a novelty item I can figure a few small situations where they still hold some value but ultimately it seems to cost too much to use them even in those cases it becomes debatable useful as you sacrifice a whole slot to what practically boils down to just +1 attack per round. You can get breach immunity, stats, damage immunities/resistance, and effect immunities via boots and you often need them in all the viable builds where you might consider the clockwork boots. I would say instead of boosting their AC I would consider adding some immunities or resistances to give them just a little more use. I am sure we can come up with a fair bit of "bad" items at least those BUR Boot can be randomized with some decent bonuses and I am guessing can even see an AC boost but I could be mistaken.
There's more than a few items like both these boots that could likely use a similar treatment.
I think I should stay out of it though since the way to get it done is coherent, succinct suggestions for improvement with equally-succinct rationale...and succinct is not in my vocabulary if you know what I mean
For me BURs should have primacy over set loot since the BUR pool is exceedingly well-populated with tons of stuff and it sucks to get crappy ones like these shadow pads or the boots of belt of legendary resilience which are really just completely useless as far as I can tell...anafaiea (sp) masterwork belt also
Roachreign needs a big boost of additional immunities (phys and/or Immunity: X) and/or improved resists cause even before the recent AC randomization change, it really provides nothing but +18 AC, much like clock boots, but it's supposed to be "good" loot from a run much harder than toy