Also KE configures its VLA less packed. 407 seats for A380, 368 seats for 748, 277 seats for 77W.
Good point ITSTours! The CEO is on record stating that they do not wish to make the economy cabin cramped like many competitors just for the sake of squeezing more pax. Seems KE understands they can earn the loyalty of their customers by offering a decent Economy class (also making Premium Economy less necessary in their business model).
Although it seems that KE is moving closer and closer to Boeing (this recent order is an example, plus the Rolls Royce service situation that many have noted), the A350 could be a compelling plane for KE when it is time to replace the VLAs. A high MTOW A359 could fit anywhere between 277 and 315-ish seats in a two-class configuration (with decent pitch and width in economy), and serve most KE routes. The A35K could fit 368-plus seats while also offering a decent level of comfort to economy passengers... and range would not be an issue at all. So, while I still think any order to replace the VLAs is Boeing's to lose, the A350 family is a very sound proposition too.
I also think A35K would be more suitable in future in terms of size and for 77W replacement, considering pressures from longhaul LCC and cost-cutting Asiana.
777-8 is heavier and KE does not need that much range.
777-9 seems a very good alternative for A380 and 748 with some downguaging, but too much for 77W replacement especially when 777-9 will carry much more passengers than 77W.
(I don't think there will be any airlines configuring 777X with 9 abreast.)
A359 however is replaceable with 787-10 (for mid-long-haul) and 787-9 (for long-haul), which they will have 20 each. And those are fairly denser compared to 77W.
Current 789 has only 8 less seats than newer 77Ws, so 78X will certainly have more seats than 77W.
My opinion is that the best future alternative would be 'Ultrafan-ed' A350-1000neo and A350-2000neo (if it ever becomes realized.)
KE can wait until then, as they have still 10 more years without needing replacements.
Also note that most of KE widebodies are directly purchased (and then capital leased), so KE will not be able to simply return the airplanes after 10 years unlike SQ.
They tend to keep using the aircraft over 20 years at which point Korean government considers them too old.