I really like the speed/cost/quality dilemma. If I get it right, social debt's purpose is to keep track of those times when you chose "cost" as a detriment.
Here is an alternative version, using a regular stress track. The idea is to make the "cost" disapear.
* succeed with style : quality and speed, no cost on your rep
* succeed or tie : quality or speed, no cost on yout rep
* succeed at a cost : quality or speed, and you take enough stress to get a tie (you cannot buy more than a tie with stress)
As usual, if your stress track is full, you may take a consequence to get what you want - but it's gonna be really bad for your rep. You will have to take care of it as it won't fade away like stress does.
I think this alternative version serve pretty much the same purpose, but only using regular fate core tools.
As a sidenote : taking care of the consequence could be done by lowering a rep score. Or, if there are no rep scores (even more streamlined!), the next minor milestone could be used to swap down the networking skill to represent the rep hit.