My only comment is that on a lot of highly fortified keeps the entrance isn't on the first floor, they make them walk up a nice exposed set of stairs at least one level and sometimes more, have fun carrying a battering ram up that!
This is another re-build.
First I started out with the map below that came from...I'm not sure where. It was just a simple, four-story, tower keep that I thought could be 'improved upon'.
So I grabbed each floor and rearranged some of the walls to turn out with a more 'functional' arrangement.
The basic idea is that the person walks in the main door and enters a fortified foyer. If you can see it, there's a portcullis (ish) guarding the inner gate plus arrow loops on either side so that if anyone breaks down the front door there's some measure of protection inside. The entrance leads to an open hall (5) with several connected rooms and a circular stair heading both up and down.
The second floor would house, in my opinion, the guards of the house. The large 'bunk room' (12) could probably accommodate four guards and two additional beds in the next room for higher-ranked servants. The murder hole, (13) would also give them another means of dealing with forced intruders in the foyer below.
The upper floors would be for the servants and for the master of the tower. My logic for this is that if anyone did lay siege to the tower, they would have to fight their way up, past the guards, before they got to the servants and to the Master.
The basement is fairly simple structure with a primary room that one enters from the circular stair and then a much larger room beside it. The roof, as shown, is basically the same design but the much larger room is actually supported by pillars leaving much larger windows on the top level.
Still no idea where to put a kitchen but I do find it interesting that the original designer added a bathroom, from what I can guess, (at the top of 16).
For most keeps the kitchen (if there was a specific kitchen) was usually a separate building altogether. Traditionally kitchens have usually always been separate buildings or wings (added later) - their incorporation into the residence proper is a fairly modern thing. If that matters at all!
What are the circles on the roof wall?
I think that I remembered somewhere that kitchens were kept separate because of the danger of fire. Unfortunately I have no idea where to keep it separate in this map. Oh well, they have magic or something and don't have to worry about it.
The circles are an attempt to represent columns around the top floor that support a roof. The idea is that the 'porch' (the place where one can go and have a seat and enjoy looking out onto the city) is at the very top of the keep so that it would be above the hustle and bustle of the street below.
I just had no idea how to show 'columns' and then a roof so just used the circles.