Newsflash, I'm not reverse engineering anything, it's pratically common knowledge both at Bulbapedia and Serebii.net.
"Aside from the high stats shared by most legendary Pokémon, many of them are only available once to the player in a given save file, and to obtain another legitimately, one must trade with another game. The gender of most legendary Pokémon is unknown (though there are four notable exceptions inLatios, Latias, Heatran and Cresselia), and all but Phione and Manaphy are unable to breed in captivity, even with Ditto." - From Bulbapedia.

You pointed out Slaking, guess why he isn't even considered a pseudo-legendary. Truant, that's why.


Sure there will always be exceptions to the common point, like how you pointed out Phione, but what I said is what is basically lined out for legendaries. High average base stats, prohibitions in usage in both competitions and Battle Frontier battles (there are some exceptions, like Rotom and Event Pichu). Of course it's all lined out by Game Freak when they create their games and how the Legendaries fit into the overall canon of the games, but they do folow a set pattern for most of the times. 

I really hope that in the future there is a Legendary that can evolve as well, but how will that change anything? If both it and it's evolution still follow at least one of the commonalities of legendaries like not being able to participate on the Battle Frontier, then it still differs from the rest of the pokemons.

I said it once and I say it again. There are rules, guidelines, whatever you want to call them. If there weren't any, who would stop anyone from naming any pokemon Legendary or Pseudo-Legendary? That would screw up competitions, rarity of the pokemon and simply would not make any sense in the games.

You keep describing how people have reverse engineered what must be needed to have a legendary status, and keep acknowledging that the developers ignore this when they feel like it. Here is the news flash, PLAYERS DON'T LABEL LEGENDARIES! You can call whatever pokemon you want by whatever title you want, but that doesn't make it true. I used Slaking as an example to illustrate how trying to apply a set of rules to a system that is arbitrarily decided is pointless.

I also have no idea why you keep harping on battle frontier et al. You realize plenty of legendaries can be used in them correct? Heatran, Cresselia, any of the legendary trios, etc. The ones that are banned are due to excessively high stat totals which, while common, is not constant amongst legendaries.

Nothing stops you from calling pichu a legendary, but it won't be unless Nintendo gives it that label. If Nintendo does then, well, it is a legendary. It is just a title. It is like being called a General in the army. You will find a lot of commonalities, and see a lot of patterns to it. Ultimately though even if something matches all the rules it might not be a General, and a few that are severely lacking in certain areas will be.

Competitions also don't ban strictly on legendary status. Garchomp is widely banned from competitive play, as is Wobbufet and its pre-evolution whose name I have forgotten. Moltres is viewed as unusable by comparison, and you would likely be mocked for trying. Same with Shamin normal forme I believe, but it might be floating in the mid teirs. I don't think Celebi has faired much better.

Nintendo has an official list now, but previously any pokemon over 50 was not allowed along with a list of banned pokemon. Many legendaries weren't on it, but Tyranitar was excluded by name, and by round about since there is no legitimate way to get him sub 55. Dragonite had similar issues before they released a level 50 event version of him.

Did you really do Voltorb Flip enough to acquire Ice Beam? Seems a legendary effort on its own to me.

Palkia and Abomasnow are going to have to work together on Lance in my case...