OK, resolved this myself (see below), but I thought my little adventure here might be of value to others, so I decided to post it anyway. Also, I'm open to other solutions anyone might have that would be more elegant than what I have done.
OK, so... getting into 2013, now. I updated our Standard.ipt, and initially converted the "Colors" to the new "Appearance" global standard. Then, I found out that the new Appearances makes Rubber reflective... and any metal surface just... frankly, for my money... stupidly reflective. THEN, I found that I could NOT get the reflectiveness to turn off. It looks like the Brass material gets this "Brass - Satin" Appearance tied to it, and under the Appearance Properties-Metal settings, you can change the "Finish", but all of them... super reflecty. Looks stupid, IMO. Don't want it. So, this all happened because I updated to the new Appearances format. So THEN, I try using an older .ipt to create a new Standard.ipt, this time NOT converting to "Appearances", and instead retaining the old Color Styles... which produced the not-so-bloody-reflective effect desired.
However, NOW, when I start a new part, I get the "Style conflict" msg for "Color:Rubber - Black - Version 1.1, Color: Titanium, Material:RUBBER, materialILICONE..." and so on. OK, so lets go to the Style Library Manager... oh, but wait... "Colors" and "Materials" are no longer IN the Style Library Manager, so I can't delete them. It's as if these Styles have gotten pushed out to the Style Library, but now in a format that the Style Library Manager interface no longer recognizes...
OK, in the course of writing this all out, I found it. The conflicting "Colors" and "Materials" can be deleted from the "Inventor Material Library" of the Appearance Browser, and the "Inventor Material Library" of the Material Browser, respectively... NOT through the "Style Library Manager" as some (read: I) might expect. Now, I may well push the document styles out to the style library, and manage them there... but that's for another thread...
seen a number of posts from you recently concerning the Style Library, maybe this link will help;
Here is an article about the Color and Appearances Libraries in 2013. It's pretty informative.
But does it help in reality?
Creating unique materials and colors for all members of the Autodesk CAD family is a big and useful step for the future. On the other hand, I'd like to see same colors and appearances for 2012 parts now in 2013. Legacy colors and materials should be available, until the user decides to use the new ones.
For me, this is a big startup problem for 2013. The sooner a solution is available, the better ..
There are definitely some pluses and minuses to this new set up. For those users who work across many of Autodesk's products, this can be a very welcome tool. From here going forward it will be quite useful. But the obvious drawback, as you stated, was the issues with legacy parts and their colors or styles no longer being available. It would be nice to be able to have all of those still available, but it looks like the frustrating work around is going to be re-creating those styles yourself. This is reminiscent of a similar issue when Styles were introduced in Inventor 9.
I am actually quite impressed with the ability to control the transparency and index of refraction for any material in the appearance library. It makes for much clearer and life like parts. We are currently in the process of updating our training courses for the 2013 release of Inventor, and there is going to be quite a bit of information on this topic in our 2D Drafting and Customization course. We will also probably be adding a free mini-course about dealing with the Colors and Appearance libraries to our YouTube channel in the coming weeks.