So I've been thinking of getting some World Championship Decks from past formats. Previous formats really intrigue me, and I think it'd be really cool to experience them. The only problem is I don't know which ones are good, or what decks of that year I should get. Does anyone have any recommendations? I don't want to purchase a pair only to find out one was a hard counter to the other. I also don't really want the 2011, 2012, or the 2013 ones. I know those formats very well (well, not so much 2011), and they weren't good enough to the point that I want to replay any of them.
Any help would be appreciated; thanks!