I think valor makes more sense than expertise... especially with the min/max differences with different AC's. Expertise could go many different ways, valor wouldn't be perfect but it would at least give an idea of experience... even though we all know experience does not equal skill in this game... it still makes more sense than expertise in my opinion.
Also... expertise could be exploited much like a twink in lowbie. I would not be surprised to see people running 1199 expertise as a poor example and being min/max'd to the gills... just for the advantage. Can't do that with valor.
We shall see...
Valor for entire legacy would work but not per toon. My valor over my legacy is probably over 600
There are also Valor boost stims now. Which would skew it quite a bit.