Other possible solutions
I wonder maybe another solution would be start 9 channeling mages with more mana turn 1. Say 5-6 more mana than 10 channeling mages. This would give a little bonus to aggressive mages but also not hurt 10 channeling mages long game.
this is an interesting idea
Agreed... some extra mana for nine channeling mages would be interesting to try. More than about five and then there is no real disadvantage to having the lower channeling mage. It also provides more options for the early game... I would love to try a Battle Forge / Lair (near center) opening for the Beastmaster, for one example.
On the "death" of rush books... I would say that an intelligent plan with a well-crafted spell book can support a rush, or at least have an option to rush... the second-place Warlord (of all things) book is one that I would consider a good rush book
... and there were two Kallek books in the tournament (neither of which took first). It all depends on what you put in your book, and how the opponent opens to defend against various possible rush strategies... you can't ignore the possible turn two thorn push, the Divine Intervention of a Vampiress on turn three, or a wand with Hurl Meteroite at range three on turn two, just for a few examples. The reason I enjoy the game is because there are so many options.
No, I don't play on OCTGN... but have had good books played against me by good players, and feel that those two factors are much more of an impact on the outcome of a game than the inclusion of Kallek. Maybe it is too efficient? I don't know... but even as is, there is a way to play against it still.