I like this map and i dont really found anything i would liked to change when playing~ great effort on the keysounds!
Just a few things you should change:
The source should be corrected from "Tenshinranman" to "Tenshin Ranman"
And i think you should change the difficult names to a standard and accurate description like 4K Normal 7K Normal or something. I think it would be better that way.
Also about the difficulty spread i think it is justified. I don't see any reason to make a easier/harder difficulty to the song. The difficulty you chose seemed fitting enough and if it was an easier toned down map or something harder just for the sake of making it harder it would seem off to me. A thing you might want to do if you feel like it is add a third keymode to the map. Like a 6k or even a 8k beatmap.
Good luck~ starred
Edit: I forgot something
.. The Overall Difficulty of your maps should be raised to atleast 9!