I wouldn't mind having these being the basis as the new legends, especially since they were the gods from FFXI (if anyone played that game and remembers them...). I still would love seeing these as being Genbu (I think that is the turtle's name...) being Ice/steel, the bird (forgot name) being Fire/Flying, tiger being Steel, and the dragon being Dragon, maybe given a secondary typing, maybe Grass since it represents spring?
EDIT: Just realized that the turtle would get killed by fire and fight (hopefully it would have huge Def and SpD to make up for it), the bird gets killed by SR, and the dragon has a lot of weaknesses...
If they did these, I was actually hoping for a pure typing for each. Flying for the bird, Normal for the Tiger, Dark for the Turtle and Dragon for the dragon... course this probably eliminates the middle dragon but whatever lol
Last gen they had legends including Phione. Could easily do Reshi/Zek plus 3rd and a trio along with the BST 600 legendary AND throw in these 4/5.
Also, I think 651 would be a good number to stop at. That'd give us 158 new pokemon, enough ideas for everyone's happiness.