Ok, so I've seen a lot of people make 'realistic' or 'semi-realistic' heads, and a good portion of them have stunning detail in the facial structure (Sharpe19 and Qarrezel immediately come to mind). However, they're missing a crucial part of a long-muzzled animal's head structure. Please take a look at this link, paying special attention to #1: attachments.conceptart.org/for…
The caption that goes with it: 1. Temporalis- This jaw muscle originates on the side of the brain case and takes up pretty much the entire side of the skull behind the eye sockets and above the zygomatic arch. It inserts into the uppermost part of the mandible. It is a jaw-closing muscle.
This is totally atrophied or absent in quite a few of these style heads. In laymans terms, it looks like an animal face was tacked onto the front of a human cranium, and it just looks off. Most, if not all, large carnivores (and let's face it, this is 99% of what is made) have very wide heads due to these powerful muscles, and leaving the back of the head rounded like a humans with an elongated muzzle just looks jarringly inappropriate.
Especially in the case of realism, art should absolutely imitate life. When taking the time and effort to impart such attention to detail to a mask like this, it seems a rather foolish oversight to leave out such an anatomically important detail. Remember, we want these to look like viable life forms, and a creature wouldn't have an elongated muzzle if they couldn't make good use of it ;3