I would like to see an ehhancement to an answer i.e. in how a solution is applied on Stack Overflow to someones existing code example/s. Maybe right next to the users suggestion where you increase their score there is a button that says, "Apply This Solution" to the original question. When clicked the solution would show the chosen users code's solution with the suggestion. On the popup it then allows you to click "With Solution" and "Without Solution" so you can see the difference and maybe also see different resulting output as a secondary feature.
The reason this would be useful is because there are a lot of new programmers out there and this would attact a larger user base to see what the results looked like before and after. In addition, this type of solution would allow seasoned developers to explain complex behavior allowing more detailed explanations to be utilized in a with/without scenario which would greatly include a larger community of users and differentiate the answers willing to go in greater detail. This would also differentiate stack overflow more from other types of q/a sites with better code examples.