Would there be any merit in a grid-based tactical combat ruleset similar to D&D 4e or Strike! wherein:
1. Each "side" in the battle (the PCs and the monsters) pools together all of their hit points, which represent plot armor, avoidance ability, resolve, and stamina and absolutely nothing about physical health.
Any damage or healing affects a whole side's pooled hit points. When one side drops to 0, that represents the narrative moment wherein the tide dramatically turns. The combat is over, and the winning side gets to narrate their victory over the losing side. The players get to describe killing/knocking out/capturing the monsters, or the GM narrates the PCs getting killed/knocked out/captured.
The one exception is minion-type monsters and summons, who never contribute to the pooled hit points and simply fall on their own.
2. Just like in D&D 4e or Strike!, the vast majority of attack powers come with both damage and a non-damage "rider" effect. The latter is usually a debuff of some kind, and placing multiple debuffs on a single enemy has diminishing returns.
3. Just like in Strike!, flanking is incredibly effective for maximizing melee accuracy and damage, and cover is an immense defense against ranged attacks.
4. Just like in Strike!, there are very few differences in PC/monster defenses, defender-types (with marks) aside.
5. AoE is limited.
The intended result is a grid-based tactical combat ruleset wherein the optimal tactic is *not* just to focus fire. No player has to sit out a battle because enemies focused fire, and no battle gets progressively easier for the PCs just because they eliminate enemies. Minions aside, nobody can eliminate enemies.
Combatants must balance between ganging up on a flanked or defensively debuffed enemy, and spreading out their attacks to make the most of debuffs. It is still quite possible for an individual creature to be in big trouble as they find themselves, say, flanked and immobilized.
How would you improve this?