Some people may say sacrifice form for intensity, but the coaches worth their salt, in all disciplines, not just CrossFit, will tell you to maintain form first.
CrossFit does not have the hard data, otherwise it would have been published. What they do have is anecdotal evidence, which is hardly accepted in the scientific community. There is data to support theories, and ways of training, but no data that says that the CrossFit approach is the best approach for fitness.
I still like the CrossFit approach to fitness, I feel it's the best approach for military members. I've been using a randomizer app on my phone to select workouts for PT in the morning, as I've been given responsibility for training the PT failures and getting them up to standard. I think it works great, the workouts are short, intense, no injuries so far, but everyone feels like they got a good workout.
Kent