The idea of having minor abilities between levels on levels that normally don't receive anything special is kind of interesting, but... Admittedly, I am almost always DM, but I don't think I've ever viewed a level as "dead". There are always skill points to be had, hps, and a number of other advantages. I was particularly surprised that they think that the first 20 levels of cleric have 19 dead levels. If anything, every other level would be dead -- at most! -- since you don't get any new spells.
Nonetheless, the perks are interesting. Although, I'm not sure they are enough to assuage anyone from going the multi- or prestige-class route.