As sumo said, the intermediary colour on the edges can do a lot, but, I would say for an army painting perspective this level of sponge chipping is pretty fine though! If this model was on the table around 50 others done in the same way, it would look cool, and from a distance, would be a convincing effect, all depends on the levels you want to take it to.
A quick way to improve sponge chipping is it go in with a brush and put silver inside a couple of the bigger chips done with a sponge, to look like they've gouged deeper. Doing it just a couple of times on the model will sell the chipping a bit more.
As sumo said, the intermediary colour on the edges can do a lot, but, I would say for an army painting perspective this level of sponge chipping is pretty fine though! If this model was on the table around 50 others done in the same way, it would look cool, and from a distance, would be a convincing effect, all depends on the levels you want to take it to.
A quick way to improve sponge chipping is it go in with a brush and put silver inside a couple of the bigger chips done with a sponge, to look like they've gouged deeper. Doing it just a couple of times on the model will sell the chipping a bit more.