[Micah]

Right, you're going to somehow kill the guy that has the chalice, even though he's likely a Tartarian, so no remote spells can touch him, and he's got access to a lab (in a fort) that can whisk the item to any other commander in the nation, or the the completely safe lab area, or to any other nation in the game. Why don't you go ahead and kill all the guys holding those clams you hate so much while you're at it? Problem solved.

Also, a lot of nations just don't have the research potential to hit construction 8 first, even if that's the only path they researched, or nature magic to get GoH up. I think it'd be a bit unfair to completely deny them access to tart-healing.