Originally Posted by
CHOPCHOP767
Just my opinion, but not a fan of "premium plus". Why not just got with "premium" or perhaps "premier" class. As I write the latter, I suspect that might cause confusion, but Premium Plus makes me think of AA's big swing and a miss with "platinum pro" or Hyatt's misadventures with labeling us Globalists, Explorists, etc. I do like the idea of consistent branding and service standards between UA's premium economy service and UA's domestic first service though.
My guess is they're trying to get away from the now illogical naming of [international] business class being above [domestic] first. They dropped "business" in favor of Polaris, note the hard [ P ] and the premium economy branding will have two hard [ P ]'s in
Premium
Plus. Couple that with [ P ]-remier benefits and think of possibilities for alliteration:
"Premier members partake in premium products: Polaris, Premium Plus, and Premium Economy provided they pay premium phares." 
Seriously though my back-of-the-napking thinking is the new P+ seat will be comparable to the domestic F seat (excepting the leg rest) and if this "level" of product is simply rebranded as PremiumPlus fleet wide, it knocks out the awkward "first" nomenclature.
Originally Posted by
jsloan
Because somebody in UA's marketing department believes that "Plus" is part of the branding. Economy+, Premium+. That's the reason; full stop.
Could be. "Plus" has been in the marketing DNA since the beginning of Mileage
Plus.