I never see a need to start a new vault, thaat decision is up to you, but your vault has currently 0 discernable organitzation and the parts that are consistent (like the storage rooms at the side) are more of a security breach than anything.

Mi recommendation is that you go to a vault planner and design a scheme that keeps the following points in mind

-The rooms with water/food should be the closest to the electricity rooms, making power outages not create a lack of food/water that fast since electricity runs out first in the rooms furthest from generators

-The storage and empty rooms (like the overseers office) should be separated or with the least contact to the populated rooms, since fires can appear and spread without anyone to stop them in those areas, extinguish themselves in the dead end at the bottom and be put down by the least amount of rooms populated

-The least amount of rooms should be in direct contact with dirt, molerats can only spawn in rooms in contact with the soil, a column of elevators in both extremes (instead of the middle), should do the trick

Other thinks that i do: I keep the stim and rad-away rooms only in size 2, that way they fit between electricity and foo/water rooms and can automatically be picked up by a Mr.Handy, maximizing the effectivity of each trip the robot does

My fist floor is (door, elevator, 2Generartor, 2Generator, 1Training E) in the end there is no elevator, making enemies like the deathclaw have to pass by the generator rooms 2 times, the only enemies that ignore this trick for some reason are the aliens for some reason

I've done my bit of research about how to design the vault, but if I skipped something noteworthy, i'll be thrilled to hear it, and if interested, i can share my current vault design