Uh, comparing New Leaf to Wild World is like comparing Super Mario Galaxy to Super Mario 64, or Super Mario World to Super Mario Brothers. One is obviously the precursor to the other, so without Wild World you wouldn't have New Leaf. Now, without the Wi-Fi, many I played with I have no idea if they still play or not, but I still do.
I started Wild World exactly 9 years ago this month, and I'm still playing it, even with having New Leaf. They're pretty similar, but very different. Best way to describe it. New Leaf added elements from City Folk, as well as putting in stuff the original had that Wild World removed. They're both on handhelds, and personally, I think they compliment each other. Keep in mind, when Wild World came out in 2005 Nintendo fell in love with the touch screen, so EVERYTHING is on the touch screen. The only thing the above screen does is show Pete, balloons, and the night sky to name a few things. If you started with Animal Crossing in 2002, and changed with the changing games, or started with it, you'll probably hold a special place in your heart for Wild World, the top selling of the series. It's a fantastic game, and to me is kind of just the Animal Crossing of the Animal Crossing, there's no real world connection at all without the holidays.
Since they also allowed you to "lock" villagers by not completing tasks, no matter how long you stop playing, they'll all still be there- another little tidbit, if you open your gate, close it, even if you don't save when you quit, you won't get Resetti, because it saved after you opened the gate, and resumes from that save.
So, yes, even though New Leaf is the best of the series with all it did, don't think Wild World is just a crap game now, because it's the foundation upon which many future games were based.