Percentage wise melee mobs have more damage than players do. They can one shot kill at times, and 2-3 shot kills are pretty common. This is already a thing in DDO, not some theory never seen in practice.
Its only those who are too fixated on the numbers while fully ignoring the actual end results who disbelieve this.
Which is STILL false, as a ranged mob can damage you from across the room, nullifying the advantage of putting distance between you.
Example. Running EVON1 on high reaper. ForumDDO® gripes often that having to get into melee range is a disadvantage, but when the inquis (todays "this new thing" which needs a nerf because "its ranged") starts shooting from the end of the hallway, the trolls and ogres pull out bows and hit like a truck, just like they hit like trucks in melee. This nullifies the ranged advantage for players. The ranged player no longer gets to plink away from a relatively safe distance.
Meanwhile in other news, its no different for the melee, as that encounter was dangerous to them from go (not more dangerous as you claim).
What scenario are you afraid of where this hurts melee even more? The only way it is more dangerous for melee is if the melee literally choose to be ineffective by staying at range, and in that case its a L2P melee issue and not a DPS parity issue.