Purely viewed as a coach, as the guy who works under the hood, I think Steve Clarke is our most important man. There seem to be clear distinctions between Rafa and Kenny in this regard, as in Rafa was a coach, someone who could still set out teams, organize, drill etc even in the absence / resignation of some of his erstwhile 'key' men. Kenny seems to be a manager of men, and someone who advises on the attacking / on the ball side of our game, while delegating defensive organisation / pressing etc to his coaches. In this case, it's imperative we take care to look after our coaches, renumerate and recognise them. In this instance, as Kenny himself said, Clarke and Sammy.
On the whole, from the few times over the years I've actually been close enough to observe, the players all but ignore Sammy Lee during a game. He's there all game, cajoling, snarling etc, but for better or worse, he's ignored. Now while that may be the case in-game, it might be an entirely different issue on the training ground. Even if all he does is play counsellor and lay out the cones, it's ultimately the call of the men who choose to keep him as part of the staff. They're the ones who will enjoy / suffer the consequences, so only the manager makes that call. I don't think of Sammy as someone who seems to have a vital role in the set-up, unlike Clarke; he just seems to be there management change after management change, but that doesn't mean he needs replacing. A team dynamic is a lot more complicated than just having the best technical men for the job.