Long ago PC gaming was about interacting with your character and environment. A complete cerebral experience that made you feel as if you were in fact part of another time and place. It literally put you in the caves of Zork, had you Hitchhiking across the galaxy and walking in the shoes of Leisure Suit Larry all set to the backdrop of a fully realized universe. These days we see much technical achievement. Audio and video we never dreamed possible being implemented in environments that are less than imaginative.
In the 80's the experience was the pinnacle of PC gaming. To this day regardless of technical achievement have PC games been able to immerse the gamer in nearly the same fashion. If for nothing else the simple fact that they don't take enough time to immerse the gamer in the experience. They throw you in a sandbox and leave you stranded playing with nothing but sand.
In the 90's PC gaming was on a good track. The introduction of more character apendages and manipulations while still maintaining a feeling that you were in control of your actions and surroundings within the universe created. Two examples of standout titles I would point out would be Thiefeadly Shadows and Vampire:The Masquerade. These may seem like odd games to focus on and some titles others would rather be picked i'm sure, but I use these as an example of the type of pc gaming i'm focusing on here.
Both of these titles made you feel like you were responsible for every action you took and set in motion your character and the environment around you. They put you in the shoes of a character and made you feel like you were that character and a part of the universe. Not just "some guy" on a mission to reload save points. The key goal here is to make what most gamers refer to as a "non-linear" experience. This term has gotten misused, manipulated and misunderstood for far too long. A non-linear experience is not dropping me in the middle of a desert so I can walk for hours on end, the idea itself is an oxymoron. I need choices, but not just "any" choices but choices that are within the character and environment in which I am a part of. Choices that keep me interested in who I am and what I am doing while still managing to do so in a way that isn't boring and linear, but non-linear and interesting. It's called chaos theory.
Morrowind is one of the best examples of how to almost get it right, though the interactions in the game are not exactly character inspiring, more to the like of getting items and leveling up, a trend that pc gaming needs to incorporate more with immersion as it has taken the front seat and saturated the market. Leveling and collecting are both sound concepts but should not be the main focus of any game "other than pac-man and such". Collecting is more along the lines of hi-score gaming, but true "PC gaming" should always revolve around your character and environment, nothing should ever outshine those two elements.
I realize that collecting is a big part of MMO gaming and many are probably wanting to bash me about now, lol. I would at this point use Star Wars:Knights of the Old Republic "I know it was console first, but it meets the criteria perfectly"as a prime example. It is just as addicting to collect items in that game as any other "item collecting" game yet the universe and characters make it all the more logical and fit within the confines of the game to make the character and universe more enjoyable "see where i'm going here". Imagine that type of concept in an MMO and you will see what i'm getting at.
I'm turning the focus too much at MMO's at this point now though and in general I am talking about PC gaming as a whole. In general i'm trying to focus on immersive gaming which I feel has always been the staple of PC gaming. Sure some feel immersion is being dropped into the middle of a battlefield and shooting it out, some dropped in a dungeon with walls on all sides, some jumping around till their hearts content. The point is PC gaming "at its roots" has always been about immersing players in the universe and too often more than not PC gaming these days tend to focus on a catch, trick, hook...what have you, to keep the gamers attention when the character and the universe in which the character is presented is what has always set the stage for "true" PC gaming.
Consoles and PC's draw a line so close to each other these days it's almost impossible to seperate the two. Truly these ideas can be taken and used on any game in particular, but honestly these concepts were always the staple of PC gaming in general. I would like to see consoles adapt more toward the PC mentality than PC's adapt to console mentality when it all comes down to it though, and that is the point. Sadly it seems these concepts are getting lost more as time goes by.
System Shock 2 vs. Bioshock....need I say more?