Most of the Combination Disciplines use really high level of Disciplines as prerequisites (more often then not, more then one level 4+ disciplines) and/or really uncommon discipline combination.
I feel there should be a lot more of weaker combination discipline using a combination of low-level (3-) common discipline (or one discipline from the majors cam/anarch/sabbat clans, plus one or more low level of common discipline), as more vampire would have achieved the needed combination to actually experiment with it and develop the Combination Discipline.
For a combination discipline to exists, a vampire must not only have the requisite disciplines mastered, but someone with these required disciplines mastered enough had to have the interest and possibility to experiment with it until he acheived something, after a lot of trial and error... If the prerequisites includes too obscure a combination of discipline, or too high level of mastery in disciplines who are not normally found naturally in an established clan, there's really little chance that the Combination Disciplines would have been discovered in the first place...
Don't get me wrong, Combination Disciplines with uncommon/high level discipline should exists, as their creation is not entirely impossible and there's a place for them... But I feel they should represent only a small fraction of all available Combination Disciplines... That for each of those really uncommon Disciplines, there should be at least 5 disciplines that require lower level of more common disciplines.
And there's also the usefullness (from a player's perspective, since a storyteller cand bend the rules for the benefit of the story and create custom Combination Disciplines as he see fit anyway) of the content of the book to take into consideration... Sure, some Storytellers will run story were charaters are old vampire starting with a lot of experience, so they might make use of this material...
But from my own experience (it might not be representative, but i played with a lot of different groups and it was mostly the same each time), games where you start from basic character creation rules, without additionnal experience, are WAY more common, and often time by the time the campaign end, while some experience was gained and you had quite grown as a character, you probably don't have gained enough experience over the course of the whole campaign to spend on the prerequisites of most of these Combination Disciplines, plus the cost to learn the combination discipline itself, less you focus most of your gained experience into this, without really improving Attributes/Skills/Other disciplines/etc... And since learning some of these obscure prerequisite disciplines (Daimonion, Mytherceria, Temporis, Thanatosis, Obeah, Visceratika) actually require an opportunity in game that as every chance of never happening... From a player's perspective I doubt I'll really have a lot of use from the content of this book.