First of all, none of the Seabourn ships has ever been "stretched".
As far as stability... of course they are stable. BUT>>> due to their diminutive size, you will feel all sorts of motion that you would not on ships 7x her size.
On my Pride cruise last fall, we had 15 ft seas. I've experienced the same seas in ships ranging in size from the Pacific Princess all the way up to the Grand Princess. Yes, it was rough...it was uncomfortable... and Capt Berg did have to hold me steady so we could have our picture taken together. Guess I shouldn't have kept the high heels on.. but it was formal night .. and I didn't want my hem to drag.