If the airport can be added to be as realistic/high quality as others, then certainly.
However if it is a small airport with little to no historic significance (FLU in the NY region), then it shouldn’t be added.
FLU has absolutely no significance to NY aviation, partly why it was closed was because of proximity/traffic issues with LGA, it’s better to not add small airports like these. It’s just a swamp now.
However those with more significance (Kai Tak, Tegel, Meigs, Tempelhoff) can/should be added, since they will actually be used.
For ex, Meigs is a fun airport for the Dash 8. It has proper ramp space, right by the water, and has a short runway, allowing for a different experience from the larger, inland airports (Midway, O’Hare). Different feel to it.