Sheesh, talk about putting words in my mouth.
I did not mean to put words in your mouth. I apologize. Not being experienced with PPLNS you probably didn't see it, but what you said the big renters are doing would require them to know the future.
If you want to know more about pool hopping and mining reward systems you can read here:
http://bitcoin.stackexchange.com/questions/5072/what-is-pool-hoppingThe top answer is written by Meni Rosenfeld and contains a link to his analysis of mining pool reward systems, which you can read if you want to get into the details.
You get paid as a pool op to explain luck and how PPLNS works over, and over, and over ad nauseam
Noooooooooooo...

I need to use bitcoin stackexchange more. I can just copy-paste the questions in and let someone else answer for me.

I think the entire shift thing simply confuses people. I actually ignore the shift concept when I look at things. I think if there was a way to eliminate shifts and get paid for your contribution per block, it would simplify things.
I agree it would simplify and I wish it was possible. But what you describe is the proportional reward system, which is vulnerable to pool hopping (see link above).
My very first post here.. I've only been mining about 3 weeks (on an antminer s3).
Welcome to the pool, and thanks for the kind words.

I am getting slightly less payouts than my first day.. but I understand that the pool size is growing so my percentage is dropping.. the benefit is that we hit more blocks as there's more effort in the pool - so on average my payout if fairly stable.
Yeah, as pool hashrate goes up your average income is the same but the variance decreases. More info here:
http://bitcoin.stackexchange.com/questions/10731/mining-pool-hashrate-effect-on-a-miners-incomeBut note that your income will be going down if your hashrate stays the same, as the difficulty keeps increasing as long as more ASIC machines are built and start mining.
How fast is global hashpower growing:
http://bitcoin.sipa.be/How does that affect you:
http://bitcoin.stackexchange.com/questions/16526/how-does-a-difficulty-increase-affect-a-miners-income