I've been trying to create a replica of IWD2's Heart of Fury mode for Baldur's Gate 2, but I don't have many good solutions. I realize Nightmare mode in BG2:EE is the BG version of HoF, but I use vanilla BG2 and I don't know if Nightmare mode grants enemies all of the bonuses that HoF does:
+10 to hit
+10 to STR, DEX, CON, INT, WIS, and CHA
+10 to all saving throws
In addition to the triple+80 HP and increased XP.
I have a current solution for the problem, but I'm sure there's a better one.
I create one spell which the protagonist may cast at will. It makes all party members immune to that spell, and then gives everything on the map, excluding the party, the full range of HoF benefits. It also makes everything on the map immune to that same spell, to prevent it from stacking if I cast it again in battle to affect any critters on the map (summons, for example).
Also, all party members get double XP: they receive a permanent effect after death that sets their XP to 200% the normal. This roughly approximates IWD1-style XP values.
Finally, difficulty is set to Insane, to make everything do double damage.
The problem is that this requires a fair amount of management from the player. You have to cast this spell at the beginning of every round, and whenever a summons appears. You do get 1 second of Improved Alacrity to make sure you can cast another spell right afterward, but it's still an extra action.
Is there any way to create an automated patch that adds these bonuses to all .cre files? I designed a custom cloak to grant the bonuses, but adding it to every monster in the game would take ages, and conflict with other mods as well.