The way Suicune's face and head are drawn in the anime and other pokemon media is not always consistent. Here's a comparison of the different ways it's been constructed. I traced each of the images. For some of the shots, I had to close Suicune's mouth and changed it so her head is in complete profile. The middle shows my own version of Suicune: A compromise of the different versions to make the most balanced, and probably most realistic and anatomically plausible, version of Suicune. There is no particular order of how the pictures of Suicune are organized.
Suicune could be called, ultimately, a herbivore head on a carnivore body, though this head does have some carnivore traits as well, such as the way the jaw opens. It has very unique anatomy that I think should be celebrated rather then be forced into the mold of a different animal. However, being based on the Qilin, it has obvious things about it's anatomy, such as it's feline-esque body (referencing the leopard/cheetah paws/claws, or coat pattern, the Qilin sometimes was depicted with) and that flexible, deer/horse-like neck. It's an amazingly unique and graceful thing to look at.
* also note that picture 7 actually is a slide of animation that comes right after 6, as Suicune lifts it's head and roars. However, since the drawing can change a little even within the same animation, I thought it would be worth it to show the difference. You can see the resemblance, though.