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I think that, generally speaking, shinies that look too similar to their regular colors [garchomp family, togepi family, avalugg, etc] is a greater offense than snot green, piss yellow, and neon pink ones.
The ONLY exceptions to this rule are Leafeon and Glaceon, having their colors be the same but a tad brighter makes them look really nice and should have been the regular colors.
On the topic of shiny eevees Gen 6 Espeon doesn't look as terrible anymore. Jolteon and Flareon look like shit though