Often drifting wind conditions in the Ionian and Corfu
Very crowded in the main season (August in particular)
The amount of flotilla fleets can block picturesque ports
Avoiding the flotillas can be difficult but it helps to sail a good distance the first day (often Sunday) and it is really helpful therefore to start on a Saturday. Usually the assisted bareboat and flotilla fleets will remain in the area between Lefkas, Meganisi and Kefalonia / Ithaka.
Also note that the region of the southern Ionian even further south is extremely attractive. Usually the megayachts (mega yachts) and motoryachts or gulet motorsailers will visit only briefly. More information on my yacht charters guide.