Rift tests a different set of skills than just killing. 1) [b]Rift forces you to play over a wide area of the map[/b] - Rift forces you to play in your spawn, their spawn, and in the middle of the map. That's a lot of areas that Survival doesn't deal with. 2) [b]Rift forces you to play with your team[/b]. - In Survival, you can 1v3 fairly easily, but you have to be coordinated to score in Rift thanks to the rapid respawns. 3) [b]Rift rewards both aggressive and passive play.[/b] - Play aggressive to get the Spark and push, and play passive to prevent a score. All in all, Rift requires a much wider range of skills than Survival. Now, I do have problems with Rift. 1) Inconsistent and unpredictable spawns often cost rounds. 2) Sides don't flip after scoring, so one team has spawn advantage on certain maps. 3) Respawns are insanely fast, so it makes it difficult to score against an evenly matched team. The enemy respawns right there, but your teammate respawns across the map. You almost have to wait on Heavy or a super to get an advantage. 4) Very difficult to play as a solo player since it requires good teamwork and coordination.

I'm just going to say it I believe Marathon will have a very similar game mode and Bungie is in the process of deciding where to put it

I think there should be more objective based game modes instead of one and 3 different flavors of elimination