Strange experience: I just retired my old GI irons (heavily offset) and replaced them with a new set (also GI irons, but with minimal offset).
Here's where it got weird. I battle a slice. I've never successfully overcome it, apart from a couple of seasons many years ago when a pro taught me to break my hands through the ball and my h'cap threatened to plummet into the single figures. Anyway, I gave up golf for a decade for various reasons, took it up again a couple of years ago...along with the slice. I've never had the time (or money for lessons) to really get rid of the slice properly since I resumed playing, so I do what I know you never should do, and set up for a slight draw with a somewhat closed club-face at address, and reduce the slice to a manageable fade.
At least that's what I was doing with my old GI (offset) irons. I tried my new (minimal offset) irons at the range this weekend, and noticed something strange - setting up for a draw, with a closed club-face, produced a slight draw. Squaring the club-face at address produced a straight shot, or sometimes just a slight fade, but it never produced a real slice. As it happened, I had my old (offset) 5 iron in the car. Dragged it out, set up square, swung....watched the ball rocket to the far right-hand side of the range and out of sight - a true hacker's slice.
I guess there are other factors at work here - weighting in the club affecting my swing, etc, along with modern GI iron technology versus 1990s GI iron technology. But why an offset iron encourages me to slice whereas a non-offset iron doesn't, I can't fathom....
Incidentally, my new (non-offset) irons are Tour Edge Exotics, XCG-3. I picked up a new-old-stock set on ebay for a song, really. So far, I'm loving the lack of offset (and Tour Edge's product, generally).