Well skull towers boost can be… if they hit you or your troops slow you down like boosted spikes. skull towers will shout iced bombs
So all bases could become unbeatable since also the time is very close when you reach the castle gate, if you add slowdown for each bomb thrown become an impossible raid.
Agree with oPelle.
Besides, if a high lvl skull tower properly hits your troops, the troops are dead anyway, no need for slowing down their corpses