C) The difference between Panarin and Bonino is that Panarin is a winger and Bonino is a center. You're not going to win a cup without a quality #3C. You can win a cup (and many teams have) without multiple elite wingers.
In my opinion we did just that. Or rather, we did have 3 quality C's, Bonino just wasn't one of them.
We did pretty good in the regular season, despite Bonino's presence for 80% of the game, where he was such a net negative he dragged everyone around him down. He wasn't visible against Columbus, he wasn't visible against Washington and only started to show against Ottawa. He was pretty good in his two final games, after which Rowney had to replace him on the center chart and we manage to win a Cup again...
1. From my view, Bonino ain't all that and a bag of chips.
2. As shown above, my opinion is that it's Cullen who is/was the more important centers of the two. If say next year Cullen isn't here and Bonino gets paid a massive contract. Once Cullen isn't there pulling his weight, I make a prediction that people will start to sour on Bonino and his contract real fast.
3. If you re-sign Bonino to a reasonable (low term, or at least a tradeable contract), I still think people will be less impressed with Bonino, because Cullen isn't there making the 4th line the most dangerous in the league and therefore more spotlight will be directed towards Bonino.
People were screaming for Bonino to be a healthy scratch during the regular season.
To summarize - A lot of Boninos flaws were overshadowed by Cullen's greatness. Once Cullen is gone... But by all means, if there's no deal to be made or FA to sign, keep Bonino. Just don't over commit just because there was no-one better this year.