Some additional perspective to consider with regards to Mr. Cobrin:
He was not a “finesse” drummer, but you have to look at the overall body of work with Morrissey from 1991-1997. His chops grew exponentially. For instance, whatever you may think of Southpaw Grammar with regards to the material, it would be hard to argue that his style did not fit the songs. The fills he deployed were sparing but well-chosen – that is, he picked his spots (e.g., the rabbit punches before the middle eight in “Reader Meet Author”, the snare/hi-hat hiccups leading into the verses of "Best Friend on the Payroll"). Look at the cross-sticking patterns on “Alma Matters” – that is not the performance of a naïf. I don’t think he was ever given the opportunity to show the stylistic range he developed as a drummer – which may not put him in the same league as Walker, but is certainly not amateur. Hell, almost 20 years have gone by and NOBODY has been able to play “Speedway” CORRECTLY AND TO ITS FULL RHYTHMIC POTENTIAL live (cf. Introducing Morrissey). That is saying something.
I think you also have to consider the contributions he could have added over time as a songwriter and a keyboardist. Morrissey didn’t just lose a drummer – he lost a real collaborator that showed the potential for real artistic vision and an ear for melody.
If you have not done so already, I would try to locate the Elva Snow material online. I believe the whole EP was on YouTube at one point. “Drinking & Driving,” “Could Ya,” and “Hold Me” are melodies that Morrissey would have been privileged to use. I feel they stand up to any number of Whyte, Boorer, or Tobias co-writes - and even surpass some.
EDIT: I would also throw my hat into the crowd that considers Jonny B his most skilled player, technically in service to the song. But I would also add that Gary Day was never surpassed in terms of feel and tone (e.g., "Dear God, Please Help Me," "Tomorrow" - where the bass is absolutely INTEGRAL to the overall success of the songs). Any road, Morrissey was lucky to have all of these talented men as collaborators throughout his career.