Yes.
To expand: I came from a pretty casual 10m background and was told during my interview and application process that the entire cooldown paradigm is completely different in 25s. I believed what I was told, naturally, but I didn't fully grasp how delicate the balance is. I was told that the primary difference is that, in 10s, you use CDs to mitigate periods of high damage during which your life is at stake. Whereas in 25s, your life is at stake whenever you do not have a CD active. I'd say it's pretty accurate, but doesn't fully encompass the fact that you have to know and rotate not only your own CDs, but also all of the externals that are available to you, as well as knowing how many can be afforded to you and still leave enough for your tank friend. That change in balance has been one of the most interesting and challenging things I've had to adapt to going from a 10m background to a 25. Not to mention all of the other pressures of 25 raiding.
This leads me to a question: given that you can be a large factor in my survival as a tank, how would you go about this as a DK without putting yourself in excessive danger?