Weirdly enough, a few days back on Twitter I speculated about an attack on a Russian capital ship along the lines that the Ukrainians reportedly executed i.e. busy up their air picture with a threatening air asset, then sneak in an ASM or two while they were distracted.
Apparently the weather was also a factor - a storm which covered both the Ukrainian's preparation on the shore, and chopped up the sea making detection of a sea skimming weapon more difficult.
All in all a superb attack.