During all my years in the travel industry, Carnival was always considered the "low-end" of the mass-market cruise lines. I personally never sailed with them, but considered all client reports and criticisms when recommending a particular ship. Based on performance and the latest news, I don't think anyone could convince me to recommend them, let alone go up the gangplank.
I don't know what the future holds for the company, but despite the refunds and offers of future freebies, I see nothing but a death spiral of Carnival.
Hopefully, one of the successful lines WON'T buy them to be used as a loss-leader.