Yeah, tbh I kinda want Zapdos to get Hurricane too. At one point I thought the absence of Hurricane in it's movepool compared to the other two birds meant it was gonna get Aeroblast since Entei got Sacred Fire... but it wasn't meant to be I guess.
Why would Zapdos only get Aeroblast? If any of the birds go Aeroblast I'd imagine it would be in an event where all of them got it. Entei being the only beast to get Sacred Fire makes sense since it was the only Fire-type of the trio. Plus Hurricane is still better for Zapdos because of the whole Thunder + Hurricane perfect accuracy in rain thing.
Back on Aeroblast. I'm not sure if it counts as a movepool oddity, but Aeroblast is by far the oddest Legendary signature move. Most if not all of legendary signature moves reflect their bearers' theme quite well, however Aeroblast isn't really the best move for Lugia. I get the connection with storms and all and the Pokédex saying how strong Lugia's wings are but it just doesn't feel right to me. Maybe it's just because Lugia has such a low Special Attack for a cover legend.
I'd say that was probably due to the time it was released in, Gen II. It's still the early days of Pokemon and the main demographic were kids who like flashy attacks, no kid wants to sit around increasing their Pokemon's defense. This was also a time when competitive battling also wasn't that much of a thing. So even though they made Lugia a wall they made its Signature move an attack to awe the kiddies (especially for those watching the movie) and hey, it was still a powerful attack on Lugia. Things changed of course and now while we have Legendaries getting moves according to their role like Cresselia and Xerneas, Lugia's Signature Attack sticks out as a reminder of simpler times when it wasn't adults looking for competitive viability but kids looking for something cool and flashy. Though nowadays maybe it would hurt to give Lugia a second Signature Move that helps with walling (and I guess to be fair to Ho-Oh it can get another one too).
While not as odd as Lugia "the wall" getting a Signature attacking move. I also find these Signature moves strange though they do fit with their Pokemon's theme:
Kadabra/Alakazam: Kinesis (when we think of Signature move we probably think of a stronger than usually move the sole learner wouldn't be caught without. Kinesis reminds us that isn't the case. It only increases Accuracy by 1 stage. Not only is that weak, it's also useless as it would only be useful for Focus Blast)
Exeggcute family: Barrage (giving a Grass/Psychic Special attacker a Normal-type, Physical multis-strike move which is weak even among other multi-strike moves. Why? Just why?)
Makuhita family: Smelling Salt (no idea why it isn't Fighting-type)
Latios & Latias: Mist Ball & Luster Purge (respectively)(while no bad moves overall, just why the weak Power? At least put the on par with Psyshock if not Psychic. To me a Signature move is a move you'd want on a Pokemon instead of another it would normally have)
Deoxys: Psycho Boost (while a great move, but only for Special offensive Deoxys. If you're a Physical focused of defensive Deoxys you're out of luck. And considering Deoxys gimmick of radically changing forms this stands out to me compared to other Signature moves for mixed attackers)
Victini: V-Create (WHY YOU NO LEARN OUTSIDE ORIGINAL EVENT!? Seriously, just have the Move Tutor that teach Keldeo and Meloetta it's Signature Move teach it to Victini)
Oshawott family: Razor Shell (while technically not a Signature move, it's still mostly related to the Oshawott family. While not major, it's odd that the Oshawott family, despite using shells as swords and their "Signature Move" being a Physical attack, they have a slightly higher Special Attack stat)
Zorua family: Night Daze (a perfectly fine attack, but sort of goes against Zorua's family's gimmick. If you use it while Zorua or Zoroark are still disguised you just revealed you're a Zorua or Zoroark. But that means while disguised you're either limited to 3 moves if you want to have Night Daze. Shouldn't its Signature Attack also follow the gimmick, like it using a random move of the Pokemon Zorua or Zoroark is currently imitating (and then turns to a normal attack once the Illusion is broke)?)
Greninja: Water Shuriken (same deal as the Oshawott family with Razor Shell. Greninja has a higher Special Attack but one of its Signature Move and only Signature Attack is a Physical one. And like Barrage, compared to other multi-hit moves its not that good (though its oddly the only Special multi-hit move))
And now for a true oddity (at least since Gen IV):
Vacuum Wave: Originally a Signature Move for Hitmonchan
in Gen III, there it was useful as it was a Physical attack because moves back then went on type to categorize them. But then Gen IV came and have moves category based on flavor, and they decided to make Vacuum Wave a Special move. This has pretty much made it useless to most Pokemon who get it. Since Vacuum Wave is about punching so hard the wind movement hurts the opponent (yet not powered up by Iron Fist, heck, I say it also fits Mega Launcher criteria since in Japan Aura Sphere is called "Wave Bomb") only Pokemon who you can see with that much arm strength can learn it... which are all Physical attackers with low Special Attack. To be fair there are some Pokemon who can make use of it, Riolu gets it from breeding (though since most Lucario are Physical they'd rather get Bullet Punch) and in HGSS it a was a Tutor Move letting Mew, Combusken/Blaziken, Meditite family, and Chimchar family learn it (though aside from Mew they all would prefer Physical movesets, and Mew has a lot of other Moves it would rather have). I think they should consider just looking through Special Attackers, seeing which one has hands/fist and give them Vacuum Wave just so this move could have some purpose.
EDIT:
It was his signature move in Diamond and Peral only because it didn't exist in Gen III. Needless to say, that makes it even weirder.
