Neck dive is bad design. In an era where you can model anything quickly in CAD software, the center of gravity is a trivial thing to find out, and you can find that out before you even make a prototype. If a bass doesn't stay put on a strap when you jump up and down, I won't own it. If it needs a "grippy" strap to stay put, that's still not good enough for me - any bass that's tugging at me because it's grabbing my shirt is just neck dive that's not quite as bad as one that falls if it isn't held - neither is acceptable to me.
I'm also not a fan of basses with excessive reach to the first position - the rule about the upper horn extending to the 12th fret (or a bit further) is as much about this as it is about balance - basses like Thunderbirds, even if they somehow miraculously balance, I won't buy because the reach is not reasonable over the long haul. I'm tall, so I could tolerate that better than most folks, but I have decided that if a company can't make the thing balanced and ergonomic, their bass is off the list.
Life is too short to suffer with stuff that doesn't work well.