Yeah. Why do you think that is? I dont understand why the hesitation for multiple creature types.
The Playtest mentions the possibility of being an other creature type, but not of being two creature types. For example, so far, the Eladrin can be either Fey or Humanoid, but not both.
Especially, the ones that are planar origins are super-flavorful.
• [Astral] [I would add Astral, and this also includes the Lawful Neutral, True Neutral, and Chaotic Neutral Planes]
• Celestial [= Positive Astral]
• Fiend [= Negative Astral]
• Aberration [= Anti-Astral]
• [Ethereal] [I would add Ethereal, and it be the "fifth" elemental plane]
• Fey [= Positive Ethereal]
• Shadow aka Undead [= Negative Ethereal]
The above are the planar origins.
Within the Material Plane, certain creature types somewhat resemble reallife taxonomy. Dragon and Giant seem an odd blend of Elemental and Beast, and are said to have caused the Material Plane to come into existence during the First World.
is a special descriptor for a sapient creature of any planar origin or creature type.
The continuum is from completely inhuman and elemental to more and more Human until actually Human.
I dont know of any narrative that explains this phenomenon. But the Orc seems part of it.
Maybe the Goliath descends more directly from the Stone Giant, without a Hill Giant intermediary? But the Goliath too is part of this humanization process.
When I think of the Giant, I think of the jǫtnar and their animism. It is the mountain itself, the ocean itself, the air itself, the winds themselves, the fire itself, and so on. The Giant feels highly Elemental. The 4e Giant emphasizes the elementalism. I am glad to see 5e continue this.
I see the difference between an Elemental and a Giant as: the Giant is an Elemental who is native to the Material Plane.
The Elementals are far away in the Elemental Planes and feel more abstract. Instead of the Earth Elemental, the Giant is a specific rocky feature of a particular mountain within the natural wilderness landscape. Instead of the Fire Elemental, the Giant is thermal activity of a particular volcanic region, or of a baking desert wilderness. Instead of a Water Elemental, the Giant is the frost of a particular glacier. (Also the Giant can be a particular river, lake, or sea.) Where there is an Air Elemental, the Giant is a particular cloud, a particular seasonal wind pattern. And so on.
As an aspect of the Material Plane, there is some kind of affinity between the Giants and the Human going on.