I like most of them, though there are a few to me that are meh (Heatran, Phione) and one that is bleh (Regigigas). Back when I got Pearl version I also got it with an action replay, so it was the first game in which I was able to cheat and explore beyond the defined boundaries of the game, and a lot of my cheating revolved around exploring where those legendaries were. That coupled with the fact that you could glitch your way to two (technically three counting Giratina but nobody tweaked to get that one early) of them sort of added a mythos to them as people were getting them before they were formally revealed and people (including me) were wondering what they were. It was a bit like Gen I with Mew; everybody wanted to get Shaymin and Darkrai but nobody knew a lot of details about them until Movies 12 and 13 came out (I think? It might have been 13 and 14 but I swear 14 was the one with Arceus in it..) Arceus itself was a mystery as well, especially since its event was never formally made available. It has an area, a summoning item, and even its own battle theme that to this day are unused, sort of like Deoxys. I think people are still trying to glitch their way to it to this very day, going far beyond the physical boundaries of the game in an attempt to summon it.
I do have to admit though the sheer amount of legendaries available, specifically in Platinum version, was a bit too much. You had two trios of legendaries, a trio master, three event legendaries, one standalone legendary just hanging out in a cave, another event legendary that you can get pseudo legendaries from via breeding, the legendary birds which were also available in HG/SS, the regi trio.... Some of them I can see, like the event legendaries (though they were a bit much...), the emotion trio, and the creation trio, but there wasn't much point in Regigigas and Heatran.
