Adjustable irons so you could tailor each iron to your needs without bending your clubs. Especially for the guys who go with cast clubs?!?
Just a thought
I'm sure they have some prototypes and will eventually release something like that. Probably not a priority since it would be expensive and OEM's make their money off of drivers, wedges and putters. Small margins when it comes to irons.
I don't really think it's needed, if you know your specs you can just order the clubs the way you want them. Can be a different story with a driver and even then the "importance" of adjustability is over done. Once you find the setting that works, you really should't need to change it again.
I've taken a "Super Stick" out on occasion and it is "playable" once you get used to the weird trajectories and distances. Not long, but you can play a moderate sized course with it. Yes, it's totally non-conforming, but if you would like some amusement, you should give it a try. A few balls and tees in your pocket, and one stick to carry around. Nice!