Yeah I think that sounds a lot healthier for the game and would make the most sense.
Yes! So if they die while in the process of say burst healing they will be Resurrected instead. So that would add a skill ceiling because Mercy players can prevent the death from happening before it has even occurred. So we could predict the outcome of the fight and either cast Resurrect before or after. Plus Resurrect would be able to be baited out by an enemy.