CoD games have always dipped below 60fps, always will. Especially multiplayer, you can't have a "solid 60fps" without limiting your engine in some capacity.
What would people prefer:
1) A solid 60fps that only uses 10% of the available resources 99.9% of the time, but has capacity to handle those rare occurences when there are 16 players on the same screen and lots of shit exploding?
Or
2) A stable 60fps 95% of the time that can drop quite significantly when Shit Gets Real?
Expecting 60fps throughout a multiplayer FPS is unrealistic, you'd be dialing back a lot of the hardware most of the time. Easier to get 60fps on a multiplayer racing game as it's more "controllable" and there aren't as many "potential scenarios". If you know what I mean.
Sure I'd love 60fps solid, but it doesn't happen. PC benchmarks, people usually quote Average, and I don't see why Next Gen should be any differently. This goes for CoD (which I'm not defending BTW, I distinctly dislike what the series has become), BF4, KillZone, etc.
Not saying this particular game isn't an "unoptimised mess", just wanted to comment on unrealistic Solid 60fps expectations for titles pushing the graphical envelope.