What's to hate about a feature that dials down the resolution when things get so heated that you wouldn't even notice the change if you were actively looking for it?
In theory it can be a good thing, but the problem is that there's really no single "best" implementation yet.
Rage was probably the worst I've seen. KZM was interesting as it reduces res (if it has to) when the scene is static - less likely to see temporal aliasing as a result. Brink was... well.. I don't think most people even knew about that one, but whether that's down to # of people playing or a very good implementation... *cough*.
I'd be interested to see more devs at least discuss implementation for best practise. The criteria for detecting frame drops and when it needs to be done can be unwieldy - how do you know specifically when to drop or even to raise up, and that's even if the frame is pixel fill/shader limited - are you wasting time if the bottleneck is elsewhere such as the CPU. If your frame time is perfect at lower res, when do you raise it back up without doing a seesaw of resolutions (arguably more distracting). There are a number of cases to consider for an FPS or any other game where the dynamics of gameplay can vary wildly.
*shrug*
Maybe if the devs have scripted something stupendous to happen like MechaStatenGruntZord descending from the heavens, maybe they should just damn the framerate for extra cinematic cinematography and just push the effects to 11 anyway.
But for general gameplay and taking care of hiccoughs - hard to say unless they spend enough time on it beyond the norm (as they are already making sure they can hit the target, nevermind the hiccoughs), short of scaling back everything.... again.
Bungie had some neat stuff for 1/4 x 1/4 particle upscaling (to reduce the artefacting for overlapped transparents & opaques), so I mean, they could just go right to the cause of pixel fill problems there instead. *shrug*
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Racers are pretty stable in the grand scheme, I would think.