People who have issues will be far more vocal than those who don't. Also, keep in mind that many of the complaints you're seeing come from people who aren't as knowledgeable about Android. That's not a knock against them in any way, because knowing the ins and outs of the system isn't something that everyone wants to do. But when there's a big update like this, you'll see a large influx of new users on the site who don't exactly know how everything works, and so they talk about bugs, problems, or missing features when the bugs/problems are often user error (completely unknown to the user), are due to a botched installation, or that the features have simply moved somewhere else. People don't like change, especially when change involves completely revamping what they're used to. That doesn't make it a bad update, it just means that not everyone is going to know how to take the proper steps to ensure a clean update along with being able to address issues that might come up. Now, if you were to see many long time forum members talking about major problems with the update, then you might want to take a closer look at things. But so far with ICS, that hasn't been the case.
I haven't had a single problem with ICS. Everything works the same as it did on Gingerbread or better. Is that to say that the update is perfect? No, because no update ever is. But it's an extremely stable build that's devoid of any major problems. Personally, I don't think there's any reason to wait for the update. Unless you root and make some changes, you're going to have to accept the update eventually. I say go ahead and do it now while there's a lot of people active on the site who can help if problems do come up.