Hi, John.
According to the apps engr of this part, the ADA4932 is the next-generation of AD8132 so it has a little better diff gain and phase errors. But if you will only replace AD8056, then AD8132 or AD8138 may be acceptable. Diff phase of 0.1deg is still excellent and is within the ±10deg maximum FCC specs at a customer tap in a CATV system and 5deg maximum typical consumer equipment. Diff gain and phase are somewhat cumulative over a signal chain, so each element (amplifier) in the chain must have less than the overall spec.
Additional questions:
1. Do you have a specific reason why you want to meet 0.02deg?
2. Will the difference between 0.02deg and 0.1deg have a visible effect in your system?
Regards,
Anna