For instance lets compare both Michael Gough and Robin Atkin Downes
Michael Gough who is a very good and experienced voice actor does about 60 characters in the game (e.g Ralof, Vilkas etc) while Robin Atkin Downes, an amazing voice actor who voices characters in Resistance, Uncharted, God of War, Metal Gear Solid, Gears of War, Infamous, Ninja Gaiden,Team Fortress 2 , Dragon Age and many more is stuck with just Brynjolf when he could have potentially been used for more.
Was it also necessary to let Odahviing have his own unique voice actor when you only talk to him like twice? Lynda Carter who has some of the most experience with the Series given just TWO characters?
Because of this mismanagement, some of the most important characters you meet in Skyrim such as Ysgrammor, Jurgen Windcaller Olaf One-eye and a few Jarls are stuck with the Arnold Schwarzenegger sounding guy who would normally play the generic guards...
I believe Bethesda definitely stepped up their game by providing more voices, but due to poor management we ended up hearing the same people over and over again and the few unique voices there were are only heard a couple of times.