That is certainly false hyperbole. There a lot of very useful new features in 2.10, and many people are currently successfully developing in Scala, even with its relatively slow compilation speed.

The Scala team knows compilation speed is important; they have dedicated people working on it full time. This release they made progress by creating an incremental compilation system called Zinc that is shared by Eclipse, maven, and most recently, IntelliJ. They have also said that there is no easy fix on the horizon. Improvements will take time and likely continue to be incremental in the near future.