Also I've been dying to ask this. But what other ideas were scrapped. And what other endings did you have in mind? I thought Twilight being with Valeguard was a super cute idea. Was there anything else that could've happened?
Well, originally the Doctor was going to severely attack Derpy again at the end and she was going to give him a really pitiful speech that kinda went against the whole idea of the both of them healing that would have snapped him out of it. I really felt Derpy needed to be a stronger character and NOT give in to his violence and not let him hurt her again, she needed to be a much stronger character than I had originally intended. I used to have her final original speech saved on my computer, and then wrote up a much better, stronger one, but I lost both of them when I went manic and deleted them.
What we have now I feel isn't as strong as what I came up with back then, but it's still a lot better than the original which was more or less "If it makes you feel better it's okay if you hurt me" which is absolute GARBAGE writing and I have come a long way out of my original mindset as an abused martyr where I used to think love is about sacrifice.
I had also planned for an adventure in the pony 1930s with Jitterbug pony and co who had been hired by The Master to harass the Doctor- I can't remember the exact plans but they were going to capture him.
Another one was that he was going to have an adventure with Spinel, where he shows up and finds Spinel pounding on his door demanding where the hell all the phones went and asking why HE has a phone box when no one else seems to remember what phones are. The timeline is all messed up and it turns out the reason phones even exist is because of The Doctor's meddling, and Spinel forces him to bring the phones back because he can't write for shit and it was his only way of communicating long distance and not in person. Yeah he could ask someone else to write his letters but that's annoying.
When Doc was with Octavia there were going to be more adventures with her as well, including The Pegasi of Paradise which are very colorful elaborite ponies who dance and do dramatic displays to impress the less colorful females, and they mistake Doc for a female because of his dull colors.
That's all I can think of at the moment, I know I had one potential crossover planned with Scruple (a draconequus) but that also fell through because I just didn't have time for side stuff any more.