I (and others) have said here repeatedly that I liked the player, but didn't like the contract.
I'm not sure how long you have followed the B's but I liken the Kelly situation to a FA that was signed here named Martin LaPointe. It's a long story, but supposedly Wings owner Mike Illitch got into it with Jacobs at the owners meeting and JJ instructed the GM (think it was MOC?) to hurt DET by signing away one of their FA's. LaPointe had been a key player for Detroit and won Cups with them in 97 and 98, and in the summer of 2001 was a FA. He was a physical, gritty player that was a great leader, but not a big goal scorer. So, the B's signed him to a ridiculous $5m contract, which immediately made him the target of every non-hardcore B's fan when he didn't live up to it. He was treated much the same way as Kelly has been, when the blame should have gone to management, not the player, for accepting the money.
Bergeron lived with him as a rookie and was taken under Marty's wing, and tutored by him, so he has at least one good lasting legacy in Boston. He went on to play for the Blackhawks for several seasons before retiring. Unfortunately, he's now the Dir of Player Development for the Habs, something we can dislike him for