Necropolis has not only skeletons but also vampires and riders, which are strong units. So, saying that they are weak without them is incorrect. Moreover, it is impossible to prevent them from accumulating skeletons. They will still have more level 1 creatures than you.
The Tower has very strong magic and three archers – that already speaks for itself, I won't argue further.
Conflux doesn't seem very appealing, but it is undeniable that with the right strategy, it can defeat both the Tower and the Necropolis.
So you fall at his feet hes the one who betrays you
Its the servants devotion for the decay
Stand up
There are no flowers on your grave
There are no chains
There I keep chanting for the forgotten name © Amorphis