The added weight of a forged club would completely negate any additional ball speed. You're also forgetting about the trampoline effect of perimeter weighting. Your point of iron byron is exactly right and why forged clubs are a little over rated. The point is, the advantage of a forged club only exists with a perfectly repeatable swing..
MOI or moment of inertia is a clubs resistance to twisting. An off center hit causes a club to twist resulting in a loss of energy and direction. With bulge and roll in a driver, it can also cause some nasty spin. The higher the MOI, the straighter and longer a driver should be on off center hits.
The catch, to achieve a high MOI, the center of gravity has to be fairly high in the club head. (above the equator) This seriously jacks with overall launch parameters and limits ball speed. Since they no longer use COR (coefficient of restitution) testing to determine a clubs conformity, they can't maximize ball speed due to the limited effect COG has on the new CT testing. High MOI drivers tend to have low launch, high spin in their highest ball speed ratings which is the opposite of optimum. They are straight though. The drivers on the market with a nice happy medium of COG and MOI is best. For good players, MOI limits workability and these players should select a head with a low center of gravity and minimal MOI to achieve high launch low spin for moderate workability and maximum ball speed. If you really need to shape a tee shot, thats why you have a three wood. BTW, there is no CT or COR limits on three woods. There are no conformity rules beyond 13 degrees.
I meant that forged is denser and stronger, which also means that material can be removed from non-critical areas to decrease weight. Muscle-back clubs are basically the inverse of cavity back but for a clubhead of the same mass, I'm pretty sure the sweet spot is smaller.
I know what MOI is, but when a marketing department gets their grubby mitts on terms and acronyms, it's time to worry, just like what the electronics companies do. Buzzwords may make people think they know what they're talking about but it's usually not the case and that goes for people in sales. too. They use the acronyms and buzzwords without explaining things and most people don't ask.
Also, since lateral (rotational, really) motion is used to impart the force on the ball, I think center of mass is more appropriate. What's CT? As I posted, I haven't kept up on golf club design in a long time.
As I mentioned, I think the swing is the most important thing, but many people either think they'll never be able to hit the ball as well as before if they make changes and don't feel comfortable with them. Some people just refuse to get help, so they try every club on the market in an attempt to find a solution to their problem, which just seems insane, to me. I worked with someone who seemed to buy a new set every few months and always tried to impress us with how much the retail price was. I asked about his average score and he was in the mid-90s. If he could afford them (he couldn't, really) and these clubs knocked 30 strokes off of his score, fine but why try to impress anyone with the price when we all knew he was spending more than he could afford?
I bought a set of Dunlop DDH cast stainless irons more than 25 years ago and can't think of a single reason to replace them. At the time, I couldn't hit a fairway wood to save my life, so I added a 2 iron and then a 1 iron since I have always hit long irons straight and my 1 iron goes dead straight unless I want it to fade or draw. I also think far too much emphasis is placed on distance. Most public and for that matter, private courses, weren't designed for people who hit 300+ yard drives. 250 yards was where most better players hit, so they placed hazards near that point, as well as where the average second shot would go. Now, with club and ball technology making it possible for a 5'8 160 pounder to regularly hit 300 yards, the course has become many shots shorter. Also, hitting longer means getting deeper in trouble. Or, farther into the adjacent fairway, which isn't necessarily a bad place to come in from. Distance is great but consistency and accuracy are much better, IMO.
That said, putting for eagle is pretty cool.