There's no legitimate argument to keep either outside of the (false) belief there's nobody better available.
Johnston's only praiseworthy accomplishment after the season's end is he instructed his team to trap a superior team to make up for the talent gap and thus lost quickly but closely. In other words, literally the exact same thing every single other coach in hockey history resorts to in the same lack of talent situation. Not only did he accomplish nothing praiseworthy, but proved nothing in the way of deserving confidence going forward he's capable of any better.
They brought in rutherford to win a cup in the short time he was to be here, there's articles from last summer stating as much, they didn't, thus his purpose for being here is gone other than dumping young player in the organizational dog house A as quickly as possible, which he accomplished, and player B yet to be determined but probably inevitable. If them keeping the knight's of the frown table that is this front office together for another year of delusions of grandeur leads to a trade of malkin in the vein hope of receiving more than the scraps that you can get for a player of his cap hit and nmc for a quick fix, I don't think I can mentally handle this team anymore, that would finally break me.