Interesting one.
The murder-fest sounds like the same sort of dynamic as Monopoly or Risk. That style of game doesn't seem to be commercially popular for new games these days; I don't know if that's a consideration for you. If you do go for the murder-fest, I'd suggest that there shouldn't be any murders until, say, at least half-way through the game, so that everybody gets a reasonable length of play.
Respawning players sounds like Vinci, if you've heard of it (a bit like Risk, but with strictly limited military power, and respawning countries). Respawned players come back as new characters, possibly with slightly different game aims, and the winner is based on total points rather than being the last one alive.
Either way might appeal to people; you could perhaps even set the game up so the players can choose which mode they will play. I think my preference is probably for respawning, though.