Not sure about PS3, but you can find lobbies really quickly on 360. As long as you search the popular playlist, such as TDM, and SnD, you'll be fine. As for hacking it's not as bad as a few years ago, and when you get in a hacked lobby nowadays it can be pretty fun. The amount of stupid shit you can do on that game is ridiculous.
On the subject of backwards compatibility for next gen, I don't think that's happening yet. Or at least, nothing's official. Now that PlayStation Network is the home for the CoD franchise, I don't know how they'd feel about Activision making previous titles backwards compatible for Xbox 1. If anything, Activision will probably remaster a bunch of previous CoD titles, and release it the way Halo did with the Master Chief Collection. However, if that's happening, it isn't public knowledge yet. Just wishful thinking