We've had 2 motorhomes over 40' long and now have a Newmar Ventana LE that is between 34 and 35' long. As others have said, basically geometry of a diesel pusher dictates that a shorter diesel pusher will have a lower wheelbase/overall length ratio. I agree, and have noticed that our 34' Newmar does not do quite as well as the longer motorhomes in a strong cross wind or when a truck goes by. However, as a trade off for the more nimble maneuvering, I personally think it is a good trade-off. The handling of our Newmar is very predictable, and I do not find it objectionable.
So---- as others have said again, I would drive a motorhome you are interested in and see how it handles yourself. Unfortunately the best thing to do is drive it on a windy day, which may not be easy to do.
Ed Headington
2013 Newmar Ventana LE
2013 Nissan Versa toad