Suggestion(s): I have a few suggestions: First: It would be cool to have a space dimension, where you can be in and fly around. It will have no gravity, and you can easily fly off. if you fly off by jumping off, depending on the direction you're going in you will go on that planet or just die.
I've thought that maybe there can be a open space dimension, but maybe a few others that are a space dimension but it's orbiting around a planet.
Another idea is that that there would be big entities or planets in one space dimension that if you fly off into, you would be teleported to that planet accordingly. it would stay in one place, each one very far apart, and have orbiting rocks. you could also go the extra measure and add the sun where if you hit it you would die.
Second: I would be cool to see that on gallifrey there were different animals that would spawn. You could maybe add custom mobs, or (that I preferrred) another way is that there would be normal mobs, but they can regenerate.
I've also thought about how there is only one building or city on gallifrey: the citadel. ANd time lords don't even spawn in it. they spawn just all over the place. SO my suggestion is that you add gallifreyan villages with normal people called gallifreyans, and then in the citadel there would have time lords and and they would spawn in specific places.
A fun thing I would like to see is that the timelords changed looks when regenerating. It would make them be a bit more realistic. Also it would be fun to have different characters n it to, like rassilion and also that under the citadel was the temple in which the doctor and clara been to in the episode "Hell Bent".
There's a structure on gallifrey i'd like to see which is a cave which the sister hood of karn are in