Mitja said:
Lugia learns less Water moves than Ho-oh learns Fire moves.
If you count TMs and everything, then Lugia learns more Psychic moves than Ho-oh.
But it doesn't even matter.
"We could go look for examples of pokemon learning no moves of their type, or learning more moves of another type or anything you want. Doesn't mean anything. If Lugia learnt 20 Water moves, it would still rather use a Psychic move because that's what it is strong at."
In short, number of moves a pokemon learns is not necessarily related to what type it is.
The point isn't that it learns many Water-moves, the point is, like I said in the beginning, it learns that specific move by level up, in addition to a few other moves. You said it learns Hydro Pump because Ho-oh learns Fire Blast which is the polar opposite move. But Ho-oh gets STAB from Fire Blast. Lugia doesn't get STAB from Hydro Pump. Then why does it learn Hydro Pump? It should learn a move that grants it STAB in that slot if Lugia is not meant to be a Water-type.
And they live in a lake, each. Not valid.
Lugia living in Whirl islands. Valid
I don't see the reasoning here.
What DNA said.
Read again, I asked you to give me an example. I cannot point out what's "Psychic-type nature" about Lugia because I have no idea what you mean by that. Not for Lugia (since thats what you're asking me) but in general.
Maybe "nature" is not the right word. I mean something like a relation or connection. What I mean is, what does Lugia have that explains its Psychic-type? When you look at it, what makes it stand out as a Psychic type? Well, I can tell you, IMO, nothing. There's nothing about Lugia, its basis/concept, its backstory, its natural abilities, its look. etc. Nothing.
If you look at other Psychic-types: Alakazam -> Magic; Hypno -> Hypnotism; Espeon -> Extrasensorial Perception; The lake trio, that I already mentioned -> Spirit. I could go on... Most of them has something that gives a Psychic-type "vibe" about them... Like you said, you think Lugia is fine as a Psychic-type because you've always knew it as one.
I know this is somewhat subjective because people don't look at the various pokémon the same way but if you looked at Lugia without knowing its type, but read all the other details about it (origin, dex entries, etc.), and had to guess its type, would you think of it as a Psychic-type?
Rayquaza is based on the Ziz, giant griffin that blocks out the sun with its wings -> Dragon type?
That's different. Rayquaza doesn't look like a giant griffin. The biblical monsters were merely used as references for the weather trio. A beast of the sea, a beast of the land and a beast of the sky. Groudon is not an ox and Kyogre is not very similar to the leviathan either as far as I know.
On the other hand, Lugia is a bit like Reshiram, it has traits of various creatures, including some Dragon traits to match the Ryujin and even the Beluga whale...