I really think there are two seperate issues here:
1. Captaincy
While the players might have the utmost respect for Kane, inspiring they say :

, at some point one has to ask just what is it that Kane is inspiring them to do - Jack the Ripper can be inspiring too - but in what direction! Now that was a melodramatic comment for effect only - but from it can get my drift. Some statements mean nothing until you drill down. I suspect that how Kane inspires doesn't require him to be Captain - I've heard it mentioned that his preparation is second to none - Ok it keeps being second to none without being a Captain. I've watched him in the rooms once (not on TV) - nothing visibly inspiring there. Look, he can keep doing what is claimed to be inspiring while he remains on the player list. While he is Captain we lose the chance to have a more inspiring player. With Kane our cup is half full - not a tragedy - but wasting opportunity!
2. Player
While the clubs lacks 22-28 aged players on the list, i believe even a slowing Kane is valuable on the list. For the few reasons stated above, he does have at least a modest influence on the playing list in terms of preparation - and never underestimate preparation, especially the little things like timing, routines, body readiness, proper cool-downs, listening skills, what to ask, how to ask, when to ask, who to ask all come under personal management and impacts markedly on players' performance. He's played finals too - a premiership player! He is going to valuable over the next couple of years coming on and off the bench IMO.
SUMMARY
Don't throw the baby out with the bath water. But let's at least change the bl00dy water!