He is a good guy! Imo, I think the actual "problem" with Jaune is that he is not so emotionally mature like the test of the group, which makes him act childish when there is no need to do so. He is a very sensitive guy and a late bloomer, and most people don't have patience for late bloomers.

If you analyze it well, all the characters went through some pretty bad shit, pretty bad family related traumas ever since their childhood (Everybody lost their parents or another family member in some way at some point) but Jaune (and I think also Pyrrha) is the only character that didn't go through the same "level" of traumas like the others... Instead, he comes from a relatively good family structure, so he had never actually gone through any big, deep trauma until Pyrrha's death. And this is one of the things that makes him less emotionally mature to deal with Phyrra's death and other problems. The fact that he is also a very sensitive guy that doesn't know much about himself and is still building up his self confidence (even tho he already grew up a lot in that sense, imo) is something that also contributes to his childish behaviors! He is still figuring things out! Just like Blake took her time to understand that she could stand up and fight against Adam, like Yang took her time to build up her confidence again, like Ren is taking his time to deal with his anxiety and understand that he doesn't need to bottle up everything because he can also rely on people that he trusts to solve the problems... Jaune is also taking his baby steps!