The rating system

[awpertunity]

There are quite a lot of threads on the forum regarding the issues you bring up here. I'll say a few things here though:

Yes, you are correct in saying that the points mean just about nothing the way they are awarded right now.

Your last paragraph about winning a small number of points and losing a large number of points to players in a league higher than you is actually indicating that you are at their level or higher (You are above the player in skill that only lost 8 points to you, and about equal in skill to the one that took 12 points away from you). This actually means that a promotion is quite imminent. Just play a few more games and it is very likely you will be promoted to Gifted league

You're right, the number of points awarded and taken away does not depend on the number of points or league of the opponent, but actually depends on a hidden skill rating that we are not shown. The hidden skill rating is what will also (eventually) decide your league, but there is some lag in that while your skill rating is still fluctuating.