I'd absolutely love that. We've had them in the past, OG Demon Wall and the Dark Dragon thing who's name escapes me (Antanabooga?) were both a reasonable damage check at ARR's launch but I'm not really sure why SE got so turned off the idea of putting much any pressure on DPS pre Savage since then. Whilst Pharos was a good challenge, that was more a healer check with a very healthy dose of mechanics. Even EX fights have had absurdly generous DPS checks in recent times =(
It doesn't have to be hard enrages either. SE have demonstrated that they can make fights progressively harder if the DPS aren't performing well. Thordan EX, OG Demonwall, Titan HM, A12S are a couple of good examples where the difficulty ramped up if the fight started dragging out at the end.