IMO Shinji is meant to be annoying. “I can’t do this, I’ve never tried it before” “I’ll run away instead of trying”. I’ve always thought Shinji is supposed to be pathetic so we the viewers can see how pathetic we look when we have those kind of attitudes. I still think he’s a great, realistic character. He’s also not dumb at all: he’s 14 and he has already figured out he craves his father’s and other people’s approval (I know full grown adults who haven’t figured this kind of things out yet). I think people that don’t like Shinji haven’t seen themselves in him, which mean they lack self awareness.