I posted this 2 years ago... I said that within 2 years, Riviera would be in the middle of the pack:
Now, 2 years later.. 2023 dues released...
WDW resort dues ranking:
1. OKW - $9.36
2. AKV -- $8.81
3. BWV - $8.51
4. BRV - $8.51
5. RIV - $8.50
6. BCV - $8.17
7. Poly - $7.95
8. CCV- $7.92
9. SSR - $7.86
10. BLT - $7.43
11. GFV - $7.33
So 2 years ago, RIV was about tied with OKW. It's significantly lower than OKW. 2 years ago, I said it was within 5% of AKV and BRV -- It's now cheaper than both AKV, BRV. 2 years ago, I pointed out it was within 10% of BWV -- It's now cheaper than BWV (by less than a penny difference). It's now within 5% of BCV, and within 10% of Poly, CCV and SSR.
So only WDW resorts now have dues more than 10% cheaper than RIV.. only BLT and GFV. But even those 2 resorts are only a bit more than $1 cheaper.