>>37302109Legendary and mythical ratio in genwun: 5/151 = 0.03311
Total amount of legendary and mythical Pokémon up to gen 6 + Meltan/Melmetal: 5+6+10+14+13+3+2 = 53
Total amount of legendaries and mythicals in gen 7:
>Baseline: 9>Guardian deities: 4>Ultra beasts, not counting Cosmog line: 11Most conservative case: 9
Least conservative case: 23
Legendary and mythical ratio in national Pokédex, most conservative case: 62/809 = 0.07664
Least conservative case: 76/809 = 0.09394
So, it is truly the case that the amount of legendaries, expressed in terms of percentage of Pokémon, has been increasing and gen 7 is probably the worst offender. It doesn't help that they haven't introduced enough Pokémon to keep this number low. We've gone from a mere 3% to anywhere between 7 to 9% of legendaries.
But it's too early to claim there are "too many", it's still not 10% of them and you still have over 90% of Pokémon being non-legendaries.