Inescapable logic, Cardioid! As a matter of fact, I'm recording a 12 part science fiction radio play for a paying customer. This requires beaucoup live mics, up to 8 in some cases. This stretches the limits of my dynamic mic collection to the breaking point, not to mention cables, headphone distribution, and isolation. At one point, we had live mics in 5 rooms. We have used everything from a Shure 55C made in 1938 (perfect for simulating a radio broadcast on a car radio) to AKG D112 as a vocal mic! (better than any of us thought it would be, especially for a deep James Earl Jones type voice). Among the many mics we have used, AKG D770 has shone in the role of voiceover mic. It's always intelligible, and almost never nasty. There's nothing better than that in a radio mic. Yes, the SM-7 rocks for this. I have *one*, and it is, of course, the voice of "our hero".
Once the players have established the sound of their character, it's not good to switch mics and pres a lot. Anyway, the D770 also has wicked good off-axis rejection, as you say. Its proximity effect is very usable for a vocalist, and it rocks on hand percussion, Djembe, and brass, especially trombone (live, for recording, get a ribbon). I think AKG made so many models of confusing dynamic mics, it's hard to find the ones that are good for something. My favs are D690, D770, D320B (older),D12, D112, C2000B, C414 (any type, they're all good for *something*). I've never used C4000B, no real clue, C451 (great overhead).-Richie