I’m on a mega server – Mankrik. When WotLK launched, I’d queue up with my warlock, still in my Sunwell gear, and get invited to a group within a few seconds. It was crazy. 3 in the morning took about 10 seconds at most to get an invite. I mentioned that on the forums, explaining how RDF wasn’t needed, and people accused me of lying. I wasn’t. It really was that easy to get into a heroic. But that well ran dry.
Now, it can take about 20 mins during prime time to get a group for the daily. Other than the daily or during non peak times, you’ll be waiting a while. I’ve changed from being anti RDF, to being for it.