With the exception of the High IO types (I2/I3). They still get it and the newer instances get NVMe SSDs. In other words they are making it a feature of certain types that would benefit from it.
Huh. You're right; it seems for the newer instance types only c1.medium and m1.small get swap mounts. That seems like a mistake by aws; but I guess you can a M3 instead of a M5.