This request is a general request for the wordpress software. It has it's uses for wordpress.com hosted blogs that can't add plugins that may offer this functions.
For self-hosted instances of wordpress there might be other ways, but they might be inconvenient.
For blogs at wordpress.com I already asked if that would be possible.
At Dashboard>Comments it is possible to remove the URL by clicking on the little x behind the URL a commentator entered.
I'm now requesting the same function to remove the IP address. Should there be problems with this approach the IP address could be replaced with 127.0.0.1 instead of being removed.
This serves privacy reasons. To me the IP addresses do not serve a purpose after the comment was approved and considered legit. I'd like to "forget" the IP address to be unable to do anything (whatsoever) with it.
Further an Editor (at least) can see IP addresses on comments made in the past.
Single IP addresses don't help me, but I might be able to see when one changes its ISP or when he/she is traveling or moved to another country. (Like researchers that got data from Yahoo Mail could tell that x persons moved form country A to country B)
It's others peoples privacy I'm concerned about.