All the differences in phraseology are just a massive threat for international pilots who are often flying in 2 or 3 different parts of the world with different phraseology in the space of a week.
Creates confusion in the cockpit especially if it's one of the pilots first times in the place. Often ends up with one pilot asking the other to ask again to clear things up which seems to bug the controllers, especially at busy airports.
ICAO should really insist that phraseology is standardised. Climb/Descend Unrestricted and Climb/Descend via the SID/STAR is simple and clear.