STR vs. VIT for leveling

[Atoli]

VIT, because at low levels its actually very powerful until you reach level 52. Then go strength.

All it does is give you a bigger HP pool, which is kind of pointless unless you do massive pulls and have a healer that can heal that many HP.
Like several people already said, defensive gear is important to reduce dmg taken, but VIT is just an extra cushion to fall on if all else fails so it's a waste of potential unless you feel too uncomfortable without the extra safety.

PLD shouldn't have trouble after level 40 when they get Shield Oath.

While Shield Oath is very useful in keeping hate, getting the first AoE skill at 50 had a lot more impact on me. Even with Shield Oath, Flash and rotating targets for threat combos, there is no way you can keep hate on really big pulls when BLMs and the like let loose right away. But hitting everything once with a nice AoE and applying DoTs on all the targets helps a lot to eastablish that initial threat that you can reinforce with your other abilities/skills afterwards.