I played with standard Schon shafts for 15+ years, then took a long break from the game. When I got back into it, I switched to a Z2. After a few years switched to 314-2, then Mezz, then OB, then back to Mezz. Only reason I switched away from Mezz in the first place was a quality issue with my shaft that wasn't addressed very well. However, I went back and gave it another shot and so far so good.
I don't think the smaller shafts (Z2, OB2, WX900) are inherently less accurate then the thicker shafts (314-2, OB1, WX700). I've played with all of them, and I can hit the same shots, generate the same spin, etc. with all of them. I think beginning or intermediate players get thrown off by the visual appearance of the smaller shaft, so they feel like finding the center axis is tougher. The contact patch is the same with both size shafts, and if anything the smaller shafts deflect a bit less, so any off center hits would be less off center on longer shots than the thicker shaft. There is of course a difference in feel (the smaller ones can feel more "whippy"), deflection (less with the smaller ones), feel in the fingers, or visually looking at the shaft.
That being said, I love my WX700. It definitely has a more solid hit than my 314-2, the OB Classic comes close and that's actually my backup shaft at the moment until I possibly pick up another Mezz. Deflection is virtually the same, I can adjust the same way between the 314-2, OB Classic, or Mezz WX700 and get the same results. I like the 12.5mm vs. the thicker 12.75 on the others, and I feel like I don't have to compromise the thickness of the ferrule to do so (the other LD shaft ferrules are REALLY thin, so taking down the shafts can be dicey).
For those that were thinking about switching, going to the smaller WX900 from a larger shaft will require a slight adjustment, likewise going up to a WX700 from a Z2 etc. will require some adjustment as well. However the gains are definitely worth it long term.
Scott