@Misadventure said:
When you think about having an effect, how big an effect to you hope for?
Honestly? I think about 1/3 of the time I've heard this, it has meant "I want the GM or the plot to be affected by changes of my own design, or I want to feel like my input is being accepted by the GM/staff. This tends to be a complaint I hear often, and whether said plot change idea is the best or worst ever, the player tends to feel as if the plot change is warranted and really wants it to be implemented.
However (I use HOWEVER at lot, don't I?), I find that MU and Tabletop(TT) tend to run the same trope when it comes to GM/ST railroading. You see, us story-writer types, when we envision a tabletop adventure, tend to think Beginning, Climax, Resolution, and when designing an adventure or a meta plot, we envision where we would like it to go, how we would like it to end, and some of the filler pieces that make the story and the plot exciting and make sense. So in MU and TT, I tend to see a lot of game plots and scenes where the general meaty bits of the story have already been authored; the players don't so much affect the outcome as they do help the GM deliver the end game she had in mind...
...and in that, I feel, many TT/MU players feel like they are supporting cast to the GMs story, where the static NPCs are the primary cast who initiate the major, over-arcing changes. From this point of storytelling, I feel a lot of players, definitely more than 1/3rd, are very perceptive to figuring out whether or not their characters are making any sort of dent into the GM/STs original vision.