See I wouldn't mind this all that much, except i'm not a fan of micro transactions and I don't think EA needs to be given that particular idea because they already squeeze enough money out of us sims fans already. And hey, don't get me wrong! I'm more than willing to pay a good deal of money for the sims packs because I love the game to bits, but I draw the line at micro transactions.
However, I do think you're onto a good idea here. An online pack would be pretty rad. I like the idea of taking a sim into the online world and having them live on a lot there and making friends and starting families with another sim. It would add a whole new level of drama lol!
I do really want the option for multiplayer LAN sims games though. It would be fun having my partner playing sims with me in the other room and building a house with me and controlling some of the sims in a household. So if they can work a LAN option into the online pack then I'd 100% no doubt buy it.