It is not the lack of sulfur that is the problem - sulfur doesn't do anything except pollute. When sulfur is removed, the process removes lubricity as well. But diesel fuel is made to an ASTM standard which includes a lubricity requirement. To meet the standard, refiners simply add lubricity enhancers back in.

When diesel was changed to LSD a few years back, it was a huge change compared to the change we're seeing from LSD to ULSD. ULSD can cause seals to shrink (just as E10 does) but I suspect most cases of leaking are due to systems that were marginal anyway.

One thing I've learned about fuels over the years is that they are like the weather - there's nothing you can do about them. ULSD is here to stay. The vast majority of diesel engines will not be effected. If you are worried that the refineries are not adding lubricity, add 2% biodiesel or straight veg oil.

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1984 300Sd 210k

Former cars:
1984 300D 445k (!!) (Strider) Original (and not rebuilt) engine and transmission. Currently running on V80 ( 80% vegetable oil, 20% petroleum products). Actually not, taking a WVO break.
1993 300d 2.5 275k. Current 120/day commuter
1981 300SD 188k (Hans) Killed by a deer