I Feel That Overall You Nailed The Look, However The Onlt Missing Detail Is The Missile Containers Opening Sequence, At Least I Recall Missiles Opening Up, I Never Use The Things On My NEXTs, On My Main Mech I Have Boosters For Both The Side And Back. And I Started Off With AALIYAH, You Know, The One That Says Good Luck In The Description. Anywho, The Mech Looks Spot On Overall, I Just Want To See Those Back Weapons Open.
After a brief compare with your SUNSHINE V2, I think the biggest upgrade is that you make it brickless at V3 which is really very nice. If you need my advise, I will suggest you try to put a mini fig (pilot) inside it since it's always a big challenge but more fun and playable. Keep going such nice creation~