Okay...a roundup could work if there were some basic restrictions in place. Or maybe some Amex ED/EDP-like multiplier to encourage frequent use.
uscjeff,
I simply read maybe a year ago in the now-defunct CreditCardForum that the 1.5 cpp feature was more popular than Chase had expected (and, by implication, costing them more cash than they expected). I don't now how to find that user now, but nothing has happened since then, so there's nothing necessarily authoritative about that source. If you have a Freedom or Freedom Unlimited as well as a CSR/CSP/AF Ink...well, it couldn't hurt to transfer the URs to the premium card now...there was a customer survey about possibly nerfing CF/CFU values on CSR.
I don't think they'd eliminate 4th night free entirely, but they could cap the frequency of its use...or the dollar value per use...or the dollar value per year. They'd have a number of tools.
AA as a transfer partner could breathe a lot of life back into the card...but Citi and AA seem to be drifting apart.