"While the 772 seat normally 290-310 passengers, a 332 can barely seat 230"....That's why in my posts while comparing the 777 and the A330 I said the "A330-300", and stated that the 777 and A330-200 have two completely different roles.'
Agreed! I share your opinion: thinking on UAL fleet and routing system, the A330-300s don't make sense... but to operate 332s does!
"[The A320, A330, A340] share the same cockpit, the same parts, the same procedures, etc'....cockpit, yes, but when was the last time that you saw wing parts, tail parts, or even gear parts from an A320 being fitted onto and A340? Even inside the planes are completely different (referring to the A320 fam. vs A330/340), with different seats (the 330/340 are one inch smaller width-wise), different o.h. bins, different doors (added cost right there---training and certifing 25,000 FA's on that door), etc. They are simply not the same plane! Aside from the cockpit, they are pretty much as different as night and day."'
Let's talk a bit about the points you rose:
Wings: Let's see the Airbus side: of course the wing of the 320 family is different of the one on the 330/340 family. But, although they have different dimensions, they do share similar procedures on maintenance and construction shape. The fuel tanks, the pumps, the electric circuits, and all the rest share the position, same technical logic and maintenance procedures. Now, let's see the Boeing side: don't forget that the wing of the 764 is unique. No other Boeing or whatever plane features that kind of wing. Final result on wing question: I think Airbus wins, but the minimum I can see here is a draw.
Tail: once again, the dimensions are different but the construction shape are equivalent (330 with 320 and 764 with 767/777). Once again, a draw.
Landing gear: I don't have information and I appreciate anyone could add it here.
Seats: this decision is up to each airline! This point doesn't give advantage on commonality to any product in the world. In this point, a TAM A330-200 is different than a Swissair A330-200!
Over-head bins: I see you have never entered an A330/340! The interior of an Airbus single-aisle is exactly equal to the one found inside an Airbus twin-aisle. The only difference is that on A330/340 there is an additional central over head bin. And talking about interiors, I remember you that the WC, galleys, windows, lights over head, a/c systems and commands, entertainment system capability, electric and hydraulic installations, etc found on the A330 are exactly equal to those on the other Airbuses (except the old A300 and A310). They do use the same parts and are displayed on the same positions. Also, the maintenance of it is equal on both single/twin-aisles. The family concept made by Airbus goes much further than to just share the cockpit! On the other side, a 764 offers the same o/h bins found on the 777 (but not the same found on 757s and 762s/763s). Result: once again -at least- a draw.
Doors: Airbus has three doors models. The doors of an A319/320 are INDEED equal to those found on the A330/340 (except the emergency exits over wings). By the way, FLY777UAL, F/A are not retarded! To open a door, all one must do is check the pressure level, press a button (and a security code?), rotate a bar and push to door to outside. Even myself (an ordinary passenger!), I know how to open a door! Excuse me but an airline will not spend more or less on "How to open a door" classes and speeches if the plane is a 764 or a 332! Even if the fleet is exclusively composed by another model/manufacturer! Result: although I don't know which is the door model adopted by Boeing (all I know is that the 777 door is also unique inside Boeing family), at minimum this is irrelevant and in maximum, Airbus wins.
Aspen1: exactly! To say that the 764 would replace the 762 and 763 in UAL fleet is false! The 764 would be too big for many routes flown by UAL! Thinking about Latin America, there simply would not have any difference to operate a 764 or a 777. On the other side, a 762 or a 763 do difference! The planes that should replace the 762 and 763 are those in NG versions or the A330-100/A330-200. If Airbus launches the A330-100, the A330-200 will become even more attractive for UAL. UAL would have a whole family from the A319-A320-A321 (standard and/or HGW version)-A331-A332, the 777 family, and the 744 family = 3 families. If UAL choose the 764, unless Boeing offer a huge and attractive modernisation pack (for cockpit, systems, interiors, etc.) for the 752s, 762s and 763s in UAL fleet, UAL will have 4 families: the A319-A320, the old B757-767, the new B764-B777, plus the 744.
My message can be resumed by this phrase: don't exclude so easily the possibility of seeing an A330 fleet in United colours in the future! I don't have a crystal ball; therefore I can't assure you that this will happen. Actually, nobody from here can. All I can tell you is that I consider the possibilities high and I have already for many times explained why. It just makes sense to me!
Sincere best regards
TP343, São Paulo, Brazil.