Cloudflare's announcement, as it is currently worded, deserves the understatement-of-the-centry award.
I know how to replace my TLS keys. I have no idea how to replace everything else.
It's like people who think losing my credit card number is the worst thing. No, it can be a hassle, but once I replace it I'm okay. It's everything else.
(except for the enlightened few who used PFS before Heartbleed)
That traffic could be basically anything sent through Cloudflare, it would seem.
And if it truly is only ~3000 sites, where's the list?