dialga looks like a powerful pokemon (salamence, metagross, ect.) but i just dont see that extra umph in him.
lets go down the list. (i wish i knew how to add sprites to threads... :/)
Moltres/Articuno/Zapdos
Birds of prey, birds of 3 completely different elements. beautifully legendary looks. and powerful.
Mewtwo
he looks like he'll kick your ass blindfolded lol. although he isnt exactly legendary, he is based off one.
Mew
Appears only to the purest of hearts and can learn every move. its extraordinary.
Entei/Suicune/Raikou
Same as birds.
Lugia
guardian of the seas, creates storms, his wings looks like big hands that'll wreck you lol.
Ho-oh
creates rainbows, created 3 legendary dogs, only seen by the purest of hearts.
Celebi
guardian of the forest, travels through time, leaves eggs of the future.
3 Regis + Regigigas
earths hardest materials. ice, rock, steel. faces are braille = hieroglyphics = ancient? and regigigas created these things.
Latios/Latias
can understand human language, highly intelligent, peaceful, extremely fast pkmn.
Groundon/Kyogre
good little story behind them. kyogre ripped off lugia a little imo but nonetheless powerful pokemon.
Rayquaza
i honestly thought when 3rd gen came out that this was gyarados' final evo. lol.
flies in earths ozone layer. all i can say about this pokemon. hes good offensively too.
(still think he should be gyarados evo)
Jirachi
well its definitely legendary because every 1k years it grants wishes written on its head. thats cool and all but if only they fixed its looks. its 1' tall -_-
(what wouldve been cool is a giant bear that sleeps for 1k years [hibernates] and grants wishes)
Deoxys
the alien pokemon that can shape-shift. thats cool. it looks pretty damn mean too.
a cool little story i think shouldve been behind deoxys was instead of fighting with rayquaza, it shouldve fought with mew or mewtwo.
Uxie/Mesprit/Azelf
they have a cool little description behind them on the pokedex but i really dont like their looks. small legendaries seem to not cut it for me imo. exception mew/celebi.
Dialga
controls time.
i really dont like its looks. i dont see it controlling time either. steel/dragon isnt really a type i see controlling time either. psychic/dark/flying/even ground maybe. but not steel.
Palkia
ability to distort space. travel through dimensions.
im not up to date on the pkmn movies but is this thing friends with giratina?
looks are ok on this pkmn.
Heatran
kinda ripped off groundon. not really feeling it either since it can have a gender.
Giratina
pokemon of the reverse world. banished for violence.
kinda cool its got the origin form and the altered form. ghost/dragon is also a pretty cool type. if only he had an ability where ghost and dark couldnt hurt it.
Cresselia
moon pkmn? im lost on this one.
Phione/Manaphy
are these even legendary? or just event pokemon...
Darkrai
gives people bad dreams.
they shouldve made this pokemon a ghost snake and let it sorta hover around giratina.
i dont like the looks of this pkmn.
Shaymin
same with manaphy?
Arceus
god pkmn. the idea of a god pkmn to me had its pros and cons.
pros: pkmn of every type, powerful, contributed to the story of where pkmn came from
cons: makes a pokemon too powerful and sorta overshadows the other legendaries.
and thats it.
i dont know 5th gens so if someone can shine some light on them that'll be great.