[MENTION=6792361]cthulhu42[/MENTION], in your campaign, what's the penalty for leaving a character dead and coming in with a new character?
If they are coming in at-level and same as any other PC, what you are encouraging is players to abandon existing characters to avoid a penalty. If new characters come in sufficiently disadvantaged vs. returning characters, that's not an issue.
As another concern, what happens if a PC caster declines to cast it? Especially after several deaths in the party so the caster is already down on CON? There can be some real player vs. player anger and that is is a dealbreaker on proposed rule changes. It could end up with a player sitting out a session or three until they can get somewhere with a high enough level NPC caster to bring them back.
Finally, it discourages players from playing clerics, since they know that they will sooner-or-later get tasked with this and they will pay for the sins of the other players. Now, there are other healing options that don't get the raise spells so at least it's not discouraging all healers, but still.