Today I've had a dream again that included Millie on her own! It means that I wasn't around and she saw it in first person view (it was basically like switching when I'm not there). I've only had about 2 or 3 dreams like that before, but not so stable and long. Of course it ended up with nuclear reactions caused by her superpowers Another thing I noticed is that she's always in her human form in all dreams, probably because I imagine her like that more often. I rarely have dreams with ponies, but surprisingly I've had one today that included Discord and Twi. I wonder if anybody here had experience with their tulpas in dreams too, especially them dreaming on their own. For example if Crep creeps Rizoel in his dreams somehow. That could be fun for sure.
Of course it's possible you're still wanting it unconsciously, but it's only you and you who can know it. You should realize and accept that it's not going to be RD how you know her from the show, her personality is very likely to change. It's like with human beings - their personality also change during time, especially when growing up. (for example Millie now has nothing to do with the character I based her on, only the appearance is sill very similar, but is slowly changing too)