Just too many factors that affect how a rig handles in wind and semi push. I've owned two trailers, a 28' Sunline with a Hensley hitch (Dodge gas dually)and a 27' Winnebago Minnie with a 4 Point Equalizer (Toyota Tundra) hitch and both were very stable on the road, even in crosswinds. Our Bay Star does get some semi push, but does pretty well in cross winds. I've just added a steering stabilizer to help....haven't driven it on a long trip yet to evaluate its effectiveness. But, if there are high wind warnings, I'll keep it parked!
Trailers: It's about weight distribution in the trailer, quality of hitch and anti-sway system and size, wheelbase, etc. of the tow vehicle.
Fifth wheel: Seems that few folks have trouble unless they have an undersized truck. But...I have no experience with this category.
Class C and Class A: weight, wheelbase, weight distribution, tires, tire pressure, aftermarket gear to improve performance (Summo springs, stabilizer, shocks, track bars, CHF (cheap handling fix), and ??
And, I'm sure I've missed some factors....you could write a book on the topic!