You're not going to get anything off 4K on neutral hit if you don't cancel the tackle animation. When you cancel the tackle, you are at +0 (+1 at tip range) And if I'm not mistaken, 4K on neutral hit didn't give a light positive advantage on neutral hit. The pushback and hit advantage it has now makes it a better poke, and allows it to work with things like 4H+K, 66K and 66P now.