I am obviously no expert, but from my PMUA legacy, I can say that 8F doesn't bother me too much as I write that off to a much greater opportunity for "better than E-". For instance, take DL's "most F in the industry" ads - that's nice, but it works out in the end to more F seats, a handful of EC, and that's it. On a 319, our chance of getting extra legroom (let's face it, that is the big difference, even if a wider seat is nice) is much greater than the competition. Given the frequent talk about lack of paid F pax, UA probably figured out that they tend (not always, but tend) to see at least 4 seats out of every 12 on those getting comped as ug's anyway, so why not make more room for paid E+?