Maybe instead of Whip of Erebos (you've got enough lifelink creatures as well as other stuff be just fine i think), Unflinching Courage for some boost and trample as well. Also i would sideboard something like Ranger's Guile for removal and Ready / Willing for board wipes. Why not just Sanguine Bond mainboard? +1 though.

PS: Ready / Willing is amazing in BWG.

Sanguine Bond is an awesome card that literally drains your opponents dry.

Grove of the Guardian seems not worth it I would rather have a guildgate that is more reliable in a starting hand, especially in a three color deck

4 Nykthos, Shrine to Nyx seems excessive. Like, it will come up in your hand and just be a dead land draw too often, cause of the legend rule, and the only way to create mana advantage with it is to have more than 3 devotion of a color already. Which is a little hard in three color decks. Granted, yours has lots of mana symbols, but that seems like more a reason to run guildgates, or at least colored mana anyways. Personally, I'd do 0 shrines, but if you want them I'd not do more than 2, and probably just 1.

I agree with bhrusson0 4 of those is completely unnecessary. I like where your going with it though, I'd definitely take our the Grove, that is a horrible land card. You have tons of high mana cards, not enough smaller costs to even things out, I would suggest removing some stuff for Voracious Wurm and Heroes' Reunion awesome combo. 9/9 wurm for 4 mana? plus gaining 7 life? yes please!