I think this has been suggested before, quite a while ago, but I can't remember if the idea got a warm reception or not.
My opinion is that it's a good one, because I have an extensive ignore list and at one point it had gotten so annoying to see those grayed-out threads that I started putting entire sections on ignore. I think being able to not see posts or threads by ignored members ought to be an option. I'm sure some folks don't want something like that to be the standard, but a choice would be nice.
But for some of the people on my ignore list, they post so much garbage all the time that even seeing that little portion of the information is annoying as my page is filled with that.
This is why I put Bitcoin Discussion on ignore, because there were so many spam threads being started by members on my ignore list, and I couldn't even keep up with adding new members to the list. There are so many spammers and alt accounts of same that Bitcoin Discussion is like a snakepit. Altcoin Discussion is probably even worse.