In mea sententia
Well, actually, Greek is easier than latin. Greek is confusing sometimes but its rules are straightforward. As for Latin, since has some close relationship with Greek, it developed more complications. There are so many irregular things and rules. Not to mention, the constructions sometimes can be really difficult. Lastly, Latin has lots of versatility since you can write in so many styles with your own preference, eg Julius Caesar, Cicero, and other writers have their own style and adjusting is kind of hard. Also, the endless uses of the ablative really kills while Greek doesn't have it because it uses the accusative more.