I want to present a counter-argument to the often cited notion that extra HP is wasted because you don't need it.
Needing it and wasting it are two completely different matters and the argument is mistaking them for the same.
While it is true that most encounters don't need the full amount of HP a full VIT build gives, that "extra" HP is by no means wasted. When you only have 13k HP, the healer can only heal you up to 13k and anything above that is overheal. The next time you take a 5k hit, you are at 8k. When you have 17k HP, the healer can heal you for the same and any heal that ended up as overheal in the 13k case are now turned into real, solid, raw HP. Plus your self-heals (yes DRK/WARs especially) are now all getting the same VIP treatment: they're getting turned into HP. Now you are at 17k and you take a 5k hit, you end up at 12k even though the healer only healed you for the same amount as the 13k tank.
Extra HP is not wasted. It may not be needed, but it is not wasted. If you base your argument on "not needed = wasted" then you are making a very big logical error.