Earlier quoted context omitted.
Your claim that the client has a full copy of the server's data is incorrect. By default that is the case, but removing such functionality takes only a few lines of javascript and removing the "autopublish" package (one command). Seriously, Meteor has grown up a lot recently. This stuff moves quick. I encourage you to take a look at it again, because I imagine many of your initial problems with the platform have been…
No stopping autopublish doesn't solve anything in this case. In my leaderboard example, the clients view of the highscore is dependent on all data in the collection which has to be published and the client has to subscribe to it. Even if you only want to show the best 10 scores of your 500k population, Meteor doesn't allow you to subscribe to the Mongo equivalent of "select player, score from results order by score d…
It's supported this from the day it was released - I remember hooking up something quite similar at the time. It was never purely autopublish.