It was great days battling and trading with your friends, and I can say that I miss the memories, but I don't really miss the method. First off comes the fact that none of my friends play Pokemon anymore, meaning I wouldn't really have anyone to play with, and I reckon this is a problem a lot of people would be facing, was the wireless method not implemented. Wireless trading and battling also gives much more variety, since it's not the same people you'll be facing all the time, and you have much better opportunities of getting certain Pokemon if you're looking for specifics, because, well, you have people from all over the world to trade with, whereas the link cable limits you immensely.
I've yet to see the online features of X&Y, though from my experiences with B2/W2, they could definitely improve on the trading options and features. Multiple times I've experienced running out to catch a Pokemon in an attempt to trade myself to a certain Pokemon, only for it to tell me that the Pokemon had already been traded, despite still appearing on the list. It was also kinda annoying with having to change the security options of ones internet just to be able to connect to the internet from the DS, though luckily that isn't the case with the 3DS :p But yeah, all in all, I don't really see why people would prefer the cable, and in any case, it's still a possibility :p