Keaton was probably viewed as too big a star to make shorts at Roach when talkies came in, but artistically, it might have been a good fit.
Actually, I never considered Keaton going over to Roach. What I meant was not trying to change his style so much in the talkies. But we all know that that wasn't Keaton's decision -- it was the brainstorm of the geniuses at M-G-M.
As mentioned above, Keaton wasn't too big for Educational -- in 1934, however. It was not just a step, but whole floor below Roach, but this was after Keaton's career went south because of M-G-M. Keaton probably drank before the talkies, but he didn't become an out-and-out alcoholic until the talkies rolled-in, and only because of the disastrous pictures and loss of control at M-G-M. (As I write this, no less than 5 of Keaton's M-G-M talkies on VHS sit on my shelf beside me, which I haven't viewed in over 30 years since they were first released. To be honest, not all of them were THAT bad, and most had at least a few good moments, if I recall.)
From what I've read, Keaton was kind of hoodwinked and sorta/kinda betrayed by Nicholas Schenck, but as Michael Corleone would say, it wasn't personal -- it was strictly business.
I'm not sure the average movie-goer in 1929/1930 woud have know that anything had changed regarding Keaton's studio, since some of his prior pre-United Artists pictures opened with Leo the Lion. Had he gone to Roach in 1929, Leo would have also introduced his pictures.
I"m not sure that Keaton was too big for Roach in 1929 actually -- L&H were already huge when the talkies rolled in, and they stuck with Roach until 1940, with only one non-Roach picture (THE FLYING DEUCES) made during that time -- and not until 1939.
Had he gone to Roach in 1929, or 1934, he would have presumably been given the artistic freedom alloted to Laurel and Hardy. The caveat here is that I doubt Roach was ready to start producing features regularly in 1929 -- L&H started making just one a year starting in 1930 (though PARDON US wasn't released until 1931), and it wasn't until late 1935 that L&H abandoned the shorts to concentrate exclusively on features.
It is fairly well documented that Keaton was not a businessman, nor was good with money. Harold Lloyd and Charlie Chaplin were; hence they financed their own pictures and didn't have to cow-tow to the studio heads. Despite this, Lloyd didn't fair too well in the talkies, but Chaplin had the cogliones to release CITY LIGHTS in 1931 as a silent picture.
So with Keaton at Roach, on Roach's dime, and with budgeted artistic freedom, Keaton certainly would have turned out better pictures in the early 30s, albeit shorts. He certainly couldn't have done any worse.
Most Keaton's Education shorts were pretty good (comparatively), and these seem to be closer to what he might have churned out had he gone to Roach, as opposed to what he did churn out at M-G-M. The films are betrayed by a low budget, and pedestrian camerwork and sound recording, magnified today by video transfers from what I presume to be the best survivng film elelements, which I can tell you ain't from the camera negatives!
"For all sad words of tongue and pen, The saddest are these, 'It might have been'."
John Greenleaf Whittier