Wheelbase ratio

Yes, longer WB/OL on the same chassis and coach dimensions gives better handling, particularly better tracking.

I would say yes as well.
Though there is a "Counter measure"
First some definitions.. They are different for Motor homes and trailers

SWAY. on a Trailer that's when the trailer swings side to side. but on a Motor home that's called WAG or at least what I call it

Sway on a motor home is side to side rocking.. Like fans at a rock concert holding up their BIC singing We Are The World.

WAG is when the tail wags like a dog (or the nose either one) side to side.

This is because leaf spring suspension allows the body to move sideways over the axle. TRAC BARS.. Stop this 100% (one front one rear)
(So does independent front suspension on the front end but most Motor Homes have solid front axle)

Sway bars on a Mother home try to control the side to side rocking. Many (other than Workhorse) have rubber bushings that cause all sorts of hassle when they wear out.. and you can get stronger bars too.

Finally there is a steering stabilizer like a True-Center (Blue ox) or Safe-T-Steer. I like the ones mentioned because of the "Remote recenter" feature.

Such a difference between my sold Tahoes and my current Silverado all due to increased wheelbase. Every inch is important.

The longer the wheel base, the better the ride, Weight and a tag will also make a ride improvement.

There are a lot of other things that effect the ride quality beside the WB ratio. Front end alignment, weight distribution, sway bars, tire pressure etc. Even if you have two identical MH's except for WB and the front end alignment or weight distribution is off on one, 2 ins of longer WB is not going to fix it. Chances are when you are looking to buy a MH they won't be on the same chassis or same make so test drive each one for yourself how it handles.

No question, there are a number of factors that go into how a coach rides and handles.

That is why I said: "on the same chassis and coach dimensions"

I am familiar with a very poor WB/OL but rides and handles well.

The Foretravel 34' diesel pusher. BUT (large but) they put a lot of $$ into the suspension-- 8 outboard air bags, 8 shocks, etc. $$ can overcome issues.