Spawn rates in Nether drastically decreased

After update aquatic, I noticed that ghasts were not spawning nearly as frequently in the nether as they used to (which is a welcome change), but this is not limited to just ghasts, now everything but pigmen spawn very infrequently. I can walk around for 10 minutes and not see a single Magma cube, wither skeleton or ghast.

The ghast spawn rate was way to high before, but now nothing but pigmen spawn in the nether.