Mixed STR/VIT is easiest. Full STR is too little health and full VIT is too little aggro. Put all points into STR and use a mix of fending and slaying accessories. Full STR is bad advice. It's too hard on noob healers and demands too much skill from noob tanks.

Low level paladin is discouraging because paladins are terrible at group aggro (and they don't get tank stance until 40, which SE still thinks is ok). When someone is starting out, they need positive reinforcement that they can actually tank. VIT helps with a larger health pool that feels tankish but STR is what actually keeps aggro and increases confidence.

It's more important to provide some confidence and fun than make new tanks fight for aggro from day 1. They can learn more later.