Can't fault the balance.
Still worried about the Attack Halving effect but you want that.
So can't complain.
What are your problems with the Attack Halving? That you could use it like I wrote in a earlier post or is it something different?
At least it shouldn't be the Dive-heals-Antimatter problem.
Rage potion and Beserk scare me most. In the case of a 6 preist Septuple Beserk for +42 attack that can also be dived and/or duped.
The first question is: what do you mean with Beserk/Berserk?
Another thing is that you can't halve the attack only 1 time per round/creature (have to change wording a little bit, 'base damage' instead of 'attack' ). The problem is that we can't avoid this abuse of the ability with the current game mechanic because it seems like that it only uses 1 attack value.
A solution could be that we would differentiate between permanent and temporary attack. The permanent attack could be increased with Blessing, Rage Potion or Burrow. The temporary attack would only change when you use abilities like Dive or the slowing of the Cultist. The difference is that the both attack values will be affected by permanet boosts or weakenings, but when the temporary ability wears of, it doesn't change the permanent ability.
Example: Wyrms with Dive and Blessing
Wyrm: 3|3; base damage/permanent attack (bd) = 3, temporary attack (ta) = 3
Wyrm use Dive: bd = 3, ta = 6
Blessed Wyrm use Dive: bd = 6, ta = 12
Dived Wyrm gets blessed: bd = 6, ta = 9
both Wyrms after Dive: bd = 6, ta = 6
Wyrm with Dive and Slowing: bd = 3, ta = 3
This could be difficult to code but I think that it should solve the problem with multiple Dive or the Slowing/Boost-problem.
That is the reason why i used 'base damage' instead of the normal attack.
edit: i changed the wording