If I had a bunch of money to spend on golf equipment, which I don't, I'd certainly want to try the 1iron system.
Cavity-back
irons were introduced as "game improvement"
clubs or, less euphemistically, remedial
clubs. They offer the advantage of being more forgiving than blades, but you give something up too: it's not as easy to "shape" shots with them. But the average recreational golfer just wants to hit straight, so it's a good trade.
I think "uni-shaft"
clubs would offer the average golfer the possibility of more consistent ball-striking, and I think that's something most golfers want--except for those who already have it. My question was not whether this would still be "real golf"--clearly it would--but what, if anything, the golfer would be giving up in exchange for this consistency.
I can think of one thing. Shorter
clubs have a shorter swing path radius, so they're angle of descent is a bit steeper. But if your pitching wedge had, say, the shaft length of your 5 iron, then it would also have the 5's angle of descent. I doubt the difference is very large but there would be some difference.
I think this would matter most in chipping, but I don't know that it'd make chipping worse, just different. We see some pros chipping with 3 and 5 woods now, so not everybody needs a short shaft for this.