rebby I get everything you are saying and will respond in much more detail later, but LOL please note that's why I said "all other things equal". (It's because I know there are other factors to consider like launch angle and smash factor.)
I read your longer post but quoted this one to keep things a little shorter.
At the end of the day, it sounds like we really agree on all points. As I was reading your earlier post I just kept nodding in agreement.
You couldn't be more spot on about the sole thickness either. I have the exact same experience. In fact, I had a shot tonight where I pondered this exact thing. I was in a tightly mowed fairway sitting 256y from the hole. Due to the layout of the hole, I needed to hit a soft draw to have any chance of getting anywhere close. Going long was dead, a large waste area that virtually guaranteed a lost ball, thus trying to take something off a 4-wood was out of the question. Short was fine, as long as I didn't get too far to the right (bunker). This left me with 2 choices, hit my 20' P730 3-iron (that I carry 230y) or try to pick my 18' P790 3-iron clean (that I carry 245y). I was significantly more comfortable hitting the P730 due to the slimmer sole but knew that I wouldn't be able to chase that up to the green so I hit the P790 instead (and pulled it off but that sort of contradicts the point that I'm trying to make so ignore that part).
That partially answers your question. My 3-iron is a P730 w/20' of loft built at 39" with a KBS $-Taper 125 shaft that tips the SW scale at D2.7. Total weight of this one is 419.2g. This carries 230y for me with those specs (my 1957 is virtually identical to this, with a Tour-V 125 instead). My other 3-iron is a P790 bent to 18' of loft built to 39.5" with a KBS $-Taper 125 shaft that tips the SW scale at D3.9 (mainly due to the length). Total weight of this one is actually a touch lighter at 416.7g. My carry distance for this is the aforementioned 245y (when struck flush, of course). So the extra 1/2" in length and 2' lower loft nets me another 15y of carry which I partially attribute to the hotter face. In contrast my 1957 2-iron is also bent to 18' of loft is built to 39.5" with a KBS Tour-V 125 that swing weights out to D2.7, static weight of 412.6g. I get 236y of carry out of the Miura 2-iron. In my experience with the Miura's I'd need ~15.5' of loft on that club to net the same 245y that I get out of my P790. That's getting a little strong for my comfort zone.
As I mentioned above, I use my P790 more like an extra fairway wood than I do an iron. I use it when I know that I have more room for error on all sides of my designated target. I accept the greater dispersion as a trade off for an extra 9 yards (over what I'd get out of my equally lofted, yet more precise, Miura 2-iron), in effect, it puts another shot in my bag.
I compare the P790 that I've been trying out to a hybrid more than I do a long iron. Compared to a hybrid the sole is pretty narrow and I have a little more control over the ball flight. I can't say if it's true or not (I've never carried a hybrid) but I also feel as if the P790 is more versatile than a hybrid.
As for your other comments per Blade vs "CB-style", I couldn't agree more. I could go on a rant about loft-jacking here too but I won't. Irons, true irons, are about precision, being able to place a ball as close to a specific target as humanly possible in a repeatable fashion. Using an iron design that introduces any deliberate deviations from that goal defies any logic that I can come up with.
Essentially, we're saying the same thing in a different way. When precision matters, play as consistent of a design as you possibly can (a nice compact blade fits the bill here perfectly). If you can sacrifice some degree of dispersion and/or you NEED the additional ARTIFICIAL ball speed for one reason or another, another iron design might fit your need, just don't expect the same level of PRECISION.