Maria is one of my favorite characters in the series, for a lot of reasons.
Plus, she was already in the very first episodes of Grendizer I saw. Later only, I knew she wasn't part of the "cast" at the beginning of the series.
To be honest, as I explained in other topics, I kind of blame Duke's attitude (OK, the truth is Duke has nothing to do with this, the writers are the ones to blame

) because in Japanese language he just says "Forgive me Maria", then "Grendizer", then runs away from her.
Would have it cost too much more to change the lines as "Forgive me Maria but it is dangerous if you come with me, I have to go protect the palace. Stay with your tutor, it is safer." ? Actually this is what he mostly says in the French version, which I think is better for that particular scene.
In this flashback, the other thing that bothers me is that we only see both of them. I think it would have been better to add the tutor in the scene. I would have preferred to see Duke have the tutor protect her sister after seeing their parents killed, and flee away in a ship, kiss her goodbye, and then only, see Duke run away from both of them. Shortly after, some explosion or anything, an attack, from a Vegan saucer for example, would have created a fire between them, and that would have made the tutor think that Duke died in the blast.
With that, we would have had all the most important characters of this episode in one scene, and almost everything would have fallen into place with the series. Almost ... Because there are remaining issues that are questionable:
1) how lucky they are, all of them, to flee to the same planet, in the same country, considering the immensity of the universe ?
2) how come the tutor and Maria never heard of Grendizer since they arrived on Earth ?
I would have preferred, again, that Maria and her tutor actually flee to some other planet, not Earth anyway, and somehow, the tutor (or both), after many years, hear that Grendizer is on Earth, making war against Vega. So that they learn that Duke is still alive (because Duke was the only one they knew who could fly Grendizer). I would have imagined something (don't know what yet) that kills the tutor, urging Maria to fly to Earth on her own, seek her brother with the help of her pendant, then after a more or less long research, reunite with her brother and join the team. It's still kind of blur to me but this is mostly what I would have come up with. OK, we don't have the "she-has-to-take-Grendizer-back-from-an-evil-pilot" thing, but I don't really like this part from the series anyway

.