ANA has sadly chosen the 777X over the A350 however they have chosen to order 7 A320neo and 23 A321neo. www.anahd.co.jp/en/pr/201403/20140327.html For the Boeing aircraft, the breakdown is 20 777-9x, 6 77Ws and 14 789s
ANA's A320neos will be delivered between 2016 and 2018 and their A321s between 2017 and 2023. I surprised Airbus still has such early slots although with a carrier like ANA, Airbus was making sure they weren't left empty handed after they'd lost the widebody contest.
It all makes sense - they have still 39 787 on order + 27 they operate, even more so with 777 - 3 on order + 54 they operate. To introduce new type would not be too logical. We might be happy they probably decided that 737NG are not so terrific even if they operate 18 of those and have another 7 on order (together with their subsidiaries it is 42 pcs - but a lot of those went to them.
i.e. realistically I would consider this as success. Also worth considering is that most of their 320s are old models 211 close to 20 years old, so in not so far future they will all go away, as is rapidly happening.
Looking at the current 77W fleet, the 777-9 will most likely have a 4-class cabin with just up to 300 seats. The 787-9 with a 2- or 3-class cabin will have 250 to 350 seats. I don't think there's a gap in the ANA fleet, they just have another fleet strategy.