From what I've seen people seem to think Revan has a better chance of being assassinated than xizor. Whether you like Revan or not he is still Revan. Ya know, the one who killed the dark lord malak, mandalore, and killed a dark council member with no battle whatsoever? Whether Revan has 1 ship or 1000 ships, each ship will be full of droids, sith, star fighters, and alike.
Revan is a MASTER tactition. Petty assassinations and hit and runs wont kill him. It would take something much more devious and well thought out besides saying a droid could take him.
Assassins will not kill Revan 1v1. Obviously.
But you misunderstand the argument. Revan could not survive an explosion. The assassins could blow up his ship, without even confronting him. Such as:
a. Self-destruct (hacking)
b. Reactor Core rupture
c. Engine over-heat
d. Bridge destruction
e. Suicide ram
f. Standard Bomb-planting
To name a few. Any self-respecting Star Wars assassin could do this. Or they could pull a Zam Wesel and try to kill him with bugs. This will not come down to a 1v1. Revan will be killed by explosion. Whether that is caused by assassins or an onslaught from Xizor's heavily-equipped fleets.
EDIT: For any who watch Star Wars: The Clone Wars, Ziro the Hutt was part of the Black Sun. So if you're looking for assassins/ a strike team, something similar to the team that freed Ziro from the Republic prison would probably be assembled to kill Revan.