In a game where tactical positioning is as important as it is in Mage Wars, being able to control that positioning can give you a huge advantage. There are lots of spells that allow you to restrict an opponents movement, but very few that actually allow you to move both your creatures and your opponents to where you need them. I believe Push is a viable alternative to Teleport, but currently it can be neutered by the Unmovable trait. Teleport has no such antithesis, which makes it inherently better.
Building a book without any ability to control positioning would put you at a severe handicap. And in the battle to control positioning, Teleport is indisputably the best tool for the job. It's application is not random, it is tactical and has a big impact on game play. The only time you would not want to have control over positions, that I can think of, is if everyone is simply piled in the same zone beating on each other. And if that is the case, you are missing out on a lot that this game has to offer.