I'm sorry, but I don't agree with you on the betsize part.
I do not think it has anything to do with it.
Ever since September until 2 weeks ago, thats almost 8 months,
Rival payouts have been terrible for mee too, on my measily 20/40ct. spins.
And when I say terrible, I mean TERRIBLE, awful, dramatic, a nightmare.
In December we got $30 free every day from both Dendera and Tropica, thats over 50x $30 free and I could not even come a tiny little bit close to meeting the WR on a single one of them.
It got kinda funny in the end...Oh, the daily freebie, lets see if I can lose it in less that 4 minutes again at minimum bets, just like all the other ones.
Plus all the other freebies, plus all my deposits and big bonuses, hardly any playtime and not the slightest chance to meet WR.
The worst result was a 200% match, deposited $35, starting balance $105.-, total playtrough made on minimum bets $189.-
I've had a few small cashouts in December (got lucky with some comps) and Januar,(cashed out $35 on a free 10 chip and received THE BAN) but nothing compared to deposits, so I don't think my returns have not been significantly better than yours.