Funny, I'd say the EXACT same thing. I threw an MD4 for the first time today. I plugged it into the bag for a tryout round thinking it was going to be pretty overstable. In the hand the MD4 feels exactly like a Gator, and the -3 fade had my attention.
It didn't fade. At all. If anything it felt like I had another (clunkier) Roc3 in the bag. I'd throw the MD4 hard and flat and it would bend right and stay there. I was pretty disappointed. I was expecting a big hook at the end of a straight flight with no high speed turn.
This is probably not a mid I'd ever throw again. I didn't really like the hand feel of it and the disc had an inconsistent, sluggish flight. None of the finesse of the Roc3. I don't feel like the flight numbers are right. The MD4 had some high speed turn and very little late fade. I'd put mine at 4, 4, -1, 1. Weird numbers.