New Ranking Placement System... Do Not Like, and Do Not Understand.

Yes, this is an actual question. Does the new ranking placement system work as advertised? (WARNING: There's a lot of rant here, so if you're inclined to flame when someone's upset, kindly skip to the last paragraph.)

Here's my situation: I stopped playing ranked last season because I got MUCH better teammates in normals than in ranked matches. Seeing as how I have no aspirations or desires of playing this game in any competitive way AT ALL (big shock, some people just want to enjoy a game from time to time), I go with whichever game style has me playing in the most enjoyable way. If ranked has me playing with low Bronze players who play worse than the AIs, and normal games have me playing with Silver players, I'm going to go with normals.

So fast forward to the last few days. I've been putting in games when and where I can; before or after work, usually. I manage to go 5/5 in placements. Not my best, but I figured, eh, if I was high Bronze when I stopped playing ranked matches, and I go PAR (as in, even, as in, logically, right in the middle of where I should be based on my skill), I should go right back where I was.

Only not.

For some reason, the system thought that going par on wins and losses meant that I don't belong where I was, but down in BRONZE FIVE. Where the people act like they're entitled to tell you how to do everything, and the jungles refuse to gank, or help, or not feed. So I guess it's back to normals for me for another season... I mean, it's better than having the actual, genuine desire harm people and break things because I'm wasting my life an hour at a time trying to play a game that's nothing but me trying to shout at people who don't display any level of actual intelligence.

Then again, I guess it's par for the course with how Riot designs their rankings system. You're expected to win 2/3 or 3/4 of your games just to stay where you're at. Which, to me, is insanely stupid, but hey, I'm just a guy on the Internet. What the hell do I know about game design (hint: I've made a 20 year hobby out of studying good and bad game design).

So, to reiterate my question after venting, has anyone else had this sort of problem? Am I just wrong in thinking that going even in wins and losses should keep you about where you already are? Do I have a fundamental misunderstanding as to how the ranking system works in League? Should I maybe just find a friend in high elo and have him/her carry me until I can go back to my beloved job as a support main?