No sense for a ranger? The only 2 D&D versions where a ranger couldn't wear medium were 3.5e (he could in 3e) and 4e (though he had the best light armor, just before medium). So it makes a lot of sense to not overemphasize 11 years of 46 years (in July) of D&D.
Does it synergize well with DDO-version? Not that much, because the easy access to Dex to hit/dmg in combination to the hybrid nature that also relies on Dex. But still doable.
Does it fit the idea of the Dark Hunter (as an underdark explorer/hunter)? Depends who you ask, but most will probably say no.
Does it fit this tree and the stats? No, not at all. Would need to be a STR focused build to pull it off or have several sources of max-dex up and armor penalty down to somewhat work.