From the pictures it already looks very cramped. I suggest making those rooms bigger? Especially if this is a big combat zone. Also, the pipes will probably have to be flank routes and not actually the main routes like how sd_doomsday does it.
what i'm planning is to make the pipes be flank routes for pyros and spy's, and that small room in-between the two pipes is actually going to be a building, directly next to the point on both sides, meaning that it won't be a major gameplay space, but that every single thing i have built is just a flank route, and nothing more...
(I intend on putting a full healthpack in the middle of the middle pipe, to make that gameplay space be used a little more...)
this is actually a general WIP of the map that i have intended... I through this together just now, so everything beyond what is already made is subject to change, but this is my general idea:
With everything deleted (It looks wierd, as my sketch application stopped working, so i had to physically remove the areas by deleting parts of the image) except for the things that are already made...