Let's get something straight right off the bat: violence works in videogames. In most games it makes sense to make violence the main mechanic; it's an established trope and the execution is obvious for a developer, and for the player it's immediately gratifying to blow the head off of an opponent. Violence in games is fine, it's just a shame when it becomes so widespread it works its way into games inappropriately.
Sometimes violence is appropriate...
To show my point, let's look at a game called LA Noire.
LA Noire is a game that frustrated me with its idiosyncratic interrogation mechanic seemingly more reliant on you understanding the way the developers think or getting lucky in finding an obvious clue than making logical deductions. But that's that. I liked it a lot, it was at the very least interesting and different, and even though I was sometimes pulling my hair out at the three speech options I still enjoyed the overall experience and appreciated the effort put into actually trying to make something new.
The game had one particularly weird aspect though; that being when it suddenly switched into third person shooter mode. Don't get me wrong, some of the action was fun, and in a limited capacity action scenes totally made sense. The scale didn't.
...and sometimes it isn't.
One case has Phelps chase after a film producer and sex offender, culminating in a chase across a film set, involving a collapsing scaffolding and followed by a shoot out between Phelps and... an entire mob. Perhaps his job as a detective is simply a guise for his other life as a Kryptonian, where he happily shrugs off gun wounds all the while demonstrating superb ability with any firearm he comes across. I know he's a veteran, but even still his abilities are superhuman in these segments. The juxtaposition of Phelps as a normal guy working as a detective and Phelps as the last action hero results in my impression of the game being a bizarre mix of Sam and Max and Grand Theft Auto.
Once again, there's nothing wrong with violence, but it sure would be nice to see a bit more thought and caution regarding using it, especially when you're dealing with non-action oriented titles. LA Noire is far from the only title to suffer from inappropriate and disproportionate gratuitous violence; Tomb Raider and the Resident Evil series stand out as well. Even though I have enjoyed the action in both, I couldn't help but feel that it was misplaced in a reboot of a series focussed on puzzles and platforming, and in the later games of a survival horror series.
Oh games industry, have you learnt nothing?
On the other end of the spectrum, a game series that worked violence in inappropriately and then learnt from it would be one of my favourite horror series, Penumbra.
It's less scary when you can kill it.
I love this series, and I love Amnesia: The Dark Descent, which is really the product of the work put into the Penumbra series. At the same time, I can tell you that Penumbra: Overture is the least scary game of them (if we forget Requiem, which I already have) for the simple reason that the most common monster can be killed. Permanently. With ease. You can just run up to the demonic dogs in this game with your pickaxe, your hammer or your broomstick and smack them to death. Boy, that really killed the tension! Overture was at its best when you couldn't defend yourself, such as segments putting you up against a horde of viscous spiders that will kill you almost instantaneously should you allow them to catch up on you. One of my favourite parts has you dashing through claustrophobic tunnels, setting oil fires and desperately pushing boulders to slow the oncoming deathly arachnids. One of my least favourite parts has you walk into a room and throw some beef jerky to distract a dog while you walk up behind it and smash it with your pickaxe.
Luckily, in Penumbra: Black Plague and eventually Amnesia, Frictional figured out that this mechanic really didn't work, and realised that scary enemies were nigh unstoppable enemies.
Try killing that with your pickaxe.
So if I had to make a conclusion, I'd make this one: don't rule out violence, but don't adopt it so quickly either. I'd love to see more horror games like Amnesia, and more interesting spins like LA Noire, and I really don't want to see more titles held back by an attachment to violence that needs to be broken in order to create new, interesting games.