What you ask for is not really possible. The netname is after all what is used to decide the connection.
In general if your schematic is too complex to keep track of the used labels then you have too much in a single unit. I suggest a hierarchical approach where every single design unit is small enough to parse it at a glance.
If you use local or hierarchical nets for this then you do not need to worry about what is used elsewhere in the schematic (it creates knowledge domains).
See Hierarchical or flat schematic design, what is best for me? (How to deal with multi page schematics?)
What could however be a good option would be a better way to get the default net names. One could imagine that the pin name instead of the pin number would help. And some way to prioritize certain symbols for this algorithm.