What "dilution" of shares? You'll get paid the same for a share, other things equal, on OCEAN as on an FPPS pool. The difference is that the payment from OCEAN is spread out over ~8 blocks.
If you're hashing for a while and then stop, your payouts will slowly dwindle. But that's not because your shares are getting "diluted": it's because the shares remaining be paid taper off.
As for lack of privacy, another word for that is transparency.