Just to chip in my full two cents:
I've been playing the PC version since launch, and it did indeed have a troubled launch, but improved a lot even before QLoc was brought onboard.
My system specs are as follows: Windows 8.1 Home, Intel Core i5 4440 @ 3.10 GHz, 8 GB Ram, nVidia GeForce GTX 750 Ti. Hardly a power house by today's standards, but meeting or exceeding all of the recommended requirements except for my graphics card, which is above the minimum.
The biggest early issue was that Steam decided to release the game as downloadable chunks instead of one big game file to "allow people to start playing while it downloaded," and this caused confusion, prevented pre-loading, and actually sometimes borked the game if you started playing before it was fully downloaded, etc. From what I understand, that was a Steam issue though and not WBIE.
The game did indeed have optimization issues at launch, more so it seemed with AMD hardware than Intel and nVidia, though there were issues there to. Most of these issues were actually resolved by the time of the Tanya patch, and for me, the game was playing excellent by the time of the Jason patch Offline.
While some people were having legit issues at this point, there was a host of people who _refused_ to change their settings form 1080p or reduce settings, or other practical things that are common for PC gaming. For me, early on I Optimized my game's settings via GeForce Experience and found it wanted to put me at 1600x900 but with all the bells and whistles on. Did that and BAM, the game ran great for me Offline with a solid frame rate in the high 50's.
But some people insisted they should be able to play with everything at 1080p and if not, the game is "poorly optimized." And to this day, there are still many who are trying to play the game on older laptops with i3 processors and nVidia GeForce 820m cards, both well below the minimum requirements, and insist the issue is the game and not their hardware.
Once QLoc was brough onboard, the game's quality improved even more, and now I get solid 60fps without issue, 1600x900 still with all the bells and whistles on. it looks and plays amazing Offline, and suffers from the same Online issues that the console versions have save it also has a smaller player base.
The PC version has been bashed and hated on far more than it deserved, even earlier on. I'm not saying there weren't issues, I'm not saying many didn't have legit problems, but I am saying that most of the issues were addressed and many with problems were caused by their own stubbornness or lesser hardware, and it's blown out the quality of the PC version, which is absolutely solid.
For the upcoming Kombat Pack, this is the first game in the franchise to launch on PC at the same time as consoles. It's the first time all the add-ons were released at the same time as well. The only one the PC is missing is the Gold Scorpion skin.
So, odds are in favour that these new characters will come to the PC as well.
Of course, we'll need to wait and see to find out, but people need to stop blowing things out of proportion or making a panic without actual proof.