The shape of the necks, except for the volute thing, is exactly the same.
But there have always been small differences between some necks of the same kind, a tolerance for up to 1mm (but it is unusual that it is that much) either way.
For example, the old RG560 had most of the time thinner necks then the RG550 and the 550 had a bit thinner then the 570 (not always, but most of the time). But they were all supposed to be the same. I have plenty of RG guitars with Wizard necks, and I think I would have a problem finding two that are exactly the same, it is very, very small differences, but they are there. Also, the third Rg1527 I got had 1.5mm thicker neck then my other two.
I think it is great that there are small nuances that separate one guitar from another and gives them more personality (if a guitar can have that, not sure about it :-) ).
The only time that is frustrating is when you want to find an exact backup for a favourite instrument, ask Vai about that one :-)
All guitars will feel, sound and react a little different from the others.
But as a quick answer, no, they haven’t change anything on the shape/size on the Wizard necks. But the shape is the only thing that haven’t changed, so it is not just the volute (but that is the only thing you can feel), they are built with a completely different construction then the old ones. They now use a construction described by themself like this “5pc. Maple/ Walnut Neck Material”. I could not find any good pics of that, but you can see it a bit on the second picture from the left on the RGA121 on this page http://www.ibanez.com/prestige/
, but on the picture is a 3pc neck instead of a 5pc. It is just a more solid way to build necks, they get less sensitive to weather and climax changes and are less likely to warp.
My English is bad, so it is hard to explain, but go to a shop and try one, and you will directly see what I mean, it is noting you can feel, just see.
It is too hard to explain the exact difference between the old and new neck constructions and why it is better now, with my English. So I hope some English speaking guy can take over here :-)
To end this, I like the new necks better because they feel better out of the box, they have a bit rounder fretboard edges, like a well played guitar old guitar. And they feel a bit more stable to play, witch you especially will notice when you do a tour were you travel a lot with the guitar (or just travel without a tour).
And a last thing, you people how have problem with the volute, how do you hold yoir hands when you play?
I have to play way up on the head to even feel it a little.