The rating does not affect the cap, its going to be the same for everyone they said. 5 wins should max you every week, I'm sure there will be other rewards that make it worthwhile for the hardcores though.
Definitely working as intended, and its nice not to have to get in 10 games every week, I have many toons and several teams to be on, though if your team sucks you may end up having to anyway lol. My 3v3 and 5v5 teams all went 5:0 and pwned noob faces, conquest capped for the week so back to leveling alts to 85 lol.