I think we can really see now just now many different builds you will be able to make with the new system.
Just looking at the Barbarian ONLY taking into account having to choose 6 skills out of the available 22 you get over 74,000 builds. When you add runes to that you get over 2 billion builds, then you add passive abilities and you have over 900 billion different ways you can build your character.
So even if only 10% of those are viable that's still a lot of ways to make your snowflake special.