As the owner of an ADC 10E Mk IV and a Sonus or two, yes, there's a problem, and you could call it a setup problem, but building the homemade damper described by Bob Graham allowed me to use the ADC cart in the arm of my Technics SL-1500 without all the jiggling and wobbling-- even on visually flat LPs!-- described by Graham. Woofer cones don't lie. And no, there was no downside. Lower stylus wear, less wasted amplifier power, less record wear, stable soundstage. Undamped high-compliance cartridges are great for breaking in woofer suspensions, though!
Heavy arms aren't the only candidates for damping. Consider that one of the lightest conventional tonearms ever made, the SME Series III, included a viscous damper either standard or as an option, and the case for damping looks stronger. But that was a commercial product, where the experimentation had already been done, and the damping was user-adjustable. If there are risks involved with damping, we should say that they are almost entirely with DIY damping, since it's conceivable that someone could overdamp an arm, not know the warning signs, and leave it that way.
These days, with cartridge compliance low and the ability to cherry-pick the lightest arms on the turntables we buy, it's not the problem it once was. But any time there's a mass on the end of a spring, some motion control is called for. Think about how well your car would stay under control without its shocks/dampers, especially if, like me, you drive like a hair-on-fire maniac. That's pretty much the life of a tonearm. Just as no roads are perfectly flat, neither are there any perfectly flat LPs, despite strident claims to the contrary.
I like my Shure Dynamic Stabilizer cartridges, but the brush does make some noise, and the advantage of a viscous damper is absolutely no added "brush talk", which is good, keeping in mind that an unclamped LP is basically a plate reverb.
