I like galvanic isollation because it is safe and no ground noise can disturb our systems.
1) it is not "safe", it decreases, not eliminates, the likelyhood of a catastrophic failure.
2) differential signalling is MUCH better at eliminating noise than galvanic isolation.
3) galvanic isolation of analog signals is virtually impossible unless you, in most cases, amplify the signal first - how are you going to "galvanically isolate" that amplifier. Also getting an anlog galvanic isolatator linear will be difficult and costly.
4) Maxim has 485 transcievers that are galvanically isolated, but read the datasheet as to how much they can take before you state "galvanic isollation is safe "

Erik