No big loss. Someone at Apple probably just felt sorry for anyone ignorant enough to pay to use the feature and mercifully killed it. =)
I wish they'd stop selling the pre-rolled ringtones. But that'll never happen. It's tacky enough that people have song ringtones, even tackier how much Apple charges for them.
Songs should not be ringtones. Period. You wanna know who's calling? Use various pre-installed ringtones, download some subtle, non-obnoxious sound effects, etc. If you must, use a SHORT instrumental clip from a song that has a ring-like quality to it. But if you have 30+ seconds of "Born in the USA" or "In Da Club" playing over and over again, because you left your ringer on, are away from your desk, didn't take your cell with you, and some crazy family member is calling you over and over again, then all you are doing is making everyone in the office HATE that song.
So maybe iTunes is doing a small favor by killing the feature.
Now why can't we have the old Visializer button back?? At least as an option. That I (still) miss. /rant