heroes reunion is meh at best and i cannot stress how much 4 Fleecemane Lion is a must as for sideboard Pithing Needle Quicken Supreme Verdict aside from that nice deck

Heroes' Reunion is just a filler cause I don't have another Fleecemane Lion at the moment... any other thought about how to use the slot?

What would you take out in the sideboard and how many of those three cards? Also, Quicken doesn't look like a good idea...

Quicken and Supreme Verdict do not seem helpful here. Pithing Needle is a good sideboard card against a lot of people, but not a do-or-die selection. the last Fleecemane Lion is of course a powerful pick, but I actually think that would be too many creatures.

Azorius Charm seems good to buy time or to cycle (which sets off your combo in a pinch). Maybe one mainboard? or a Cyclonic Rift ? instead of the Heroes' Reunion which seems a little weak.