If abuse is an issue, why not hash the IP with a nonce?
If you don't know the nonce, you can't match against other users-- so not useful for abuse.
But I'm skeptical re: abuse uses. For commenters, sure-- you may need to store IPs to combat abuse. But for readers? At most you would need sampled data or in-memory counters (e.g. to catch high volume bots).
Unfortunately, there really isn't any penalty for failing to minimize private data collection.
You d have a triple virtuous effect: people would stop being such insuferable asses once they understand basically their name is on the comment, readers would be completely safe because why not and abusers would be logged still.
It's even probably what most websites do: it news to me to keep the IP of every visitor, I'd have pruned them.