You can make a much stronger base than this, using a lot less dart traps. I use only 8 dart traps and it shreds everything in vanilla.You can take balanced, and make it overpowered.
Dart traps are my example. They don't do too much damage, but put 15 rows of them (stacked 2 high on each side of a corridor, with electric fences)
and that becomes overpowered.
Mind you, you have to WORK to make that, and feeding those things is not exactly trivial.
(and if you screw up and break one of the traps, it's a pita to fix)
Someone will always come up with a way to stop the zeds in their tracks on horde night, without using cheese.
Enough ACTIVE defenses, along with the player, and yes, you can be perfectly safe.
As long as we have to work hard to make it, the IMHO, it's fine.
Blood Moon: