First off, the film I posted, I hope the youtube print is close to as beautiful as my DVD copy, because FATTY AND MABEL ADRIFT has some of the most beautiful shots in any silent film. It's been a while since I've seen it, but I remember some of those shadowed and tinted shots by the sea being quite breathtaking, and the film itself works as a comedy, love story, and adventure film. Easily my favorite Arbuclkle film.
As far as assessing Roscoe, it's impossible to do. In the teens, the guy was second to Chaplin. He had an actual personality that extended beyond his physical appearance, was very graceful for a man his size, and worked with props very well. He then signed to Paramount. Based on what survives of his Paramount work, which is not much, it appears he was contractually obligated to stick to strict script stage comedies as opposed to more original material like the greats of the twenties. Had he made more films in the twenties, who knows how he would've competed with Chaplin, Keaton, and Lloyd, and therein lies the problem, we'll never know. Arbuckle was second best in the teens, but that's the equivalent to sixth or seventh best in the twenties. A true shame we'll never know his true potential.