I personally find the “hold middle mouse” to rotate camera a bit to cumbersome and counter-intuitive in the heat of battle. I takes your focus away from engaging the enemies for a second. (I tend to look around a lot) The two keys to rotate the view left or right (default key are , and .) are to slow and just doesn’t feel good to use either.
One suggestion to improve (in my opinion) the camera control is to have the two keys rotate the view in fixed degrees instead of slowly turning.
For example: If your camera is facing north and you press “rotate left” key the camera make a quick but smooth 90 degrees turn facing west. A quick double tap would result in the camera facing south, and so forth.
I think this camera method is a great alternative to the middle mouse turning. And is faster than the slow key press method that currently is in the game.
Don’t Starve uses this method, for referens. I think it works great in that game, and would work great in Grim Dawn.
That could work quite well, especially if added as an optional set of keys. 
I’d use it as well as mmb as I prefer the ability to flick to whatever direction with the mouse, but would be very handy for general view turning underground.
p.s…I think you meant 90 degrees 
I use the scroolWheel (up and down) of the mouse to turn the camera.
I have scrool up to turn right and scrool down to turn left
You’re right! Fixed it
You can do this now if you have a programmable keyboard / gamepad / mouse etc.
I use a Logitech G13 and do exactly this, although I found 90 degree increments to be too large so I have mine set to 45 degree each keypress. Actually, I have it bound to the mini joystick left & right so it kinda feels like you’re panning a movie camera.
Anyway, just program a button to hold the assigned key down for a specific length of time. The duration probably varies depending on your PC / CPU / GFX etc., but on mine 783ms give me a 45 degree rotation, and 1566ms gives 90 degrees.
You’ll have to calibrate it for your own PC. I did it by lining up a lamp post outside town with some UI component in the middle of the screen and then rotating 360 degrees with 8 key presses of 45 degrees and then tweaking the duration until it was spot on.
It actually turns out to be very reliable on the G13…I can be playing for some time, rotating the camera this way and that, and then I hit the reset view button and if I happen to be in the default orientation it hardly moves to re-center.
You can see it in action a bit in this video: https://www.youtube.com/watch?v=Y2KvSsCT0DA
The two pans while I’m running are using the programmed buttons…the pan during the Fabius fight is with the mouse wheel for precision.
Thanks, great idea. I tried it and it works well!
I just bind the rotate keys to A and D, and Q W E S are for support abilities and mana and health are bound to 1 and 2. Toggle abilities are put on quickbar 2 and Standfire is locked to shift. This puts the most used keys right under hand in a way that is most natural for me when playing most PC games. Rotating camera becomes an unconscious activity with this setup, it is almost always spinning around. I tend to click directly above the character and change direction with camera keys and I never have to mode switch in my mind in order to to engage enemies. It does cause me to have to check the map alot though.