Victini does get points for being at the start of the region's dex instead of the end, so I do sometimes forget it when mentally going through the list. But I think my answer goes to Heatran. That thing could have easily been a normal single-stage Pokemon. Hell, it even has a gender. And unlike other legendaries that don't have much of an impact on anything (the Lati duo, for instance), it isn't part of a group, it's just kind of its own entity.
If you actively hate Justin Bieber... then you don't know what "intended audience" means. Hate Twilight instead, it's far worse.