How do you feel about Anger of the Gods in place of pyroclasm? Exile is always better than having them hit the graveyard.Some space for Atarka's Command seems like it might fit well with your colors that are in this deck. It is also modal and cheap to cast.

I definitely think the deck is cool +1 from me.

Hi Muggins! Anger of the Gods is actually better but too hard to cast. RR is too difficult for this deck. You usually run low on colours with few Stars and Sphere and only 4 Groves. Instead I tried Firespout. It worked well but in the end Pyroclasm is more reliable and two damages is usually enough to kill what you need to survive long enough (like casting in turn 2 to make 2 for 1 trade is usually fine).

Regarding Atarka's Command, the card is even harder to cast as RG and do not really provide any advantages. Putting a land into play is fine but I would better be able to fetch the one I need in my deck for 1G with Sylvan Scrying.

I'm very happy you like the deck, hope you would also enjoy playing it!