This idea is simple: items crafted using the Sanctuary alchemy machine (at the end of Shadow Lairs) should have a chance of gaining UVs for movement speed and HP bonus (+2, 3, 4, or 5) when crafted. And only through the normal process by which crafts gain UVs. So 1 in 30 Shadow Lair sets would have one of these UVs on one piece, though most would be lows. But only on Shadow Lair sets that people weren't preserving UVs for.

The terribleness comes from the resulting absurd value of these items and crazy rich people constantly gunning through shadow lairs to try and craft one, spending absurd amounts of CE. And probably the worst thing would be an influx of a handful of these UVs on Snarby sets in Lockdown for the richest players. But in spite of this (and the fact that I personally don't use Shadow Lair gear at all), I would still deer-in-the-headlights want to see this happen.