I would get rid of the Leyline completely... the card hasn't been good for a long time.

Engineered explosives isn't a necessity, especially for BW tokens.

Flaying tendrils is a great sideboard card against dredge, elves, merfolk, persist creature decks, etc. These are the most difficult creature matches for tokens. It can hit master of waves and etched champion unlike Anger of the Gods. Maybe not optimal against merfolk since you do need additional removal to turn off things like Lord of Atlantis but it is still great.

Kalitas is another option against these creature decks but can be a bit slow. But it is less likely to die games 2 and 3 since your opponent will take out some spot removal. It is also another card you can bring in against Burn.

Consider another sundering growth. Opposing players bring in ensnaring bridge, enginnered explosives, ghostly prison, worship (eldrazi), etc and these cards auto-win against us often.

Selfless spirits are great. These protect you from conflagrate, anger of the gods, pyroclasm, oblivion stone, supreme verdict, engineered explosives, etc. All common sideboard cards that will massively slow down your clock. These can be good combat tricks against crrature decks. Also, you want these against combo as they put a fast clock compared to bitterblossom.