I had to sign in for this one.
Sasuke probably, having your whole family killed.
Naruto never knew his so h didn't miss out there.
Gaara was justneglected.
I see your logic. But your wrong in one part.
Knowing love even at one point of your life is better then Not knowing love and being rejected. Sasuke chose to be a loner. Naruto on the other hand was just cast out.
Level wise:
Naruto was at the lowest. why? Sasuke was part of the "Head" Uchiha family, Gaara was the son of Kazekage. Naruto..... just a trash or a demon. (Him being Minato's son is revealed later).
Emotional wise:
Gaara was idk .. a "weak kid" i guess.
Who had it tougher??
Naruto.
See people apparently put Gaara having it tougher. The problem with that is Naruto CHOSE to make friends. Gaara turned evil. And when he turned "good" and start saying thanks and etc.. guess what? He had friends.
OVERALL , in their lives Naruto had it tougher mate. Ever since he was a little kid.. while gaara had care for him and etc.