It depends what you’d value more, more frequent friendlies away to the likes of Bahrain, Jordan with (almost) guaranteed World Cup appearances and likely group stage exists, or home qualifiers against the likes of South Korea, Japan and Australia with less guarantees around the big dance. It’s all hypothetical but this whole thread is so we’ll flog a dead horse anyway.
OFC and AFC can’t combine to one thing for geographical reasons, so if it ever did collapse then you’d have to split Asia east/west, I’d say India would be the boundary. With 48 teams you’d split the 9(+2 playoffs) AFC/OFC spots into 5.5 and 4.5, which way I don’t know. West Asians/Arabs would probably be happy not to play Japan, South Korea, Australia, and vice versa. Would mean your direct rivals would those big three, China, North Korea, Vietnam and ASEAN, on top of existing OFC.
Youth WC appearances would drop, but those are, at least in my opinion, overstated in NZ player development. Players don’t suddenly play 4 games against Honduras, Norway, Uruguay and Colombia and become better, that’s a result of development as a youth player, and club environment. Even so, you’d get your qualifying games against the Asian teams to prove whether they can kick it anyway. The tournaments do help in scouting of players onto higher levels, but ultimately the cream rises to the top regardless, so the players will eventually wind up at an appropriate level.
It’d also allow for an actual meaningful continental competition. Once FIFA canned the Confeds, NZF gave up on the OFC Nations’ Cup, to the point that they weren’t planning on sending the senior team to the 2020 edition and instead using it as Olympic prep, with Des taking it instead of Hay. This was for a tournament being held in New Zealand, not even one in the islands that no one would want to play in. Instead you’d have 30 odd countries and genuine interest/competition as to how a team would compete, as opposed to the current forgone conclusion obligation.
It would also help out the situation that the Phoenix are in of being in two confederations and yet none. They would simply become a member of this new confed, and operate in the same way as Swansea does for example. It’d allow them access to all international comps, and also possibly open the door for additional NZ teams down the line.
The fact is though, travel times from Asia to NZ, let alone the islands, is probably more than to Doha/Dubai, so there’s no real advantage to point out there. There’s also a lot more revenue through sponsorship and broadcasting rights to be made by partnering with Saudi, Qatar, UAE, Iran than with Tahiti, PNG, Fiji. You could also argue they’d miss the competitive aspect of West Asia, but in terms of WC places, Japan, Korea and Australia would have to have a disastrous era not to be top 8 in the region, so reducing it to 4/5 and adding NZ and the rest probably wouldn’t dilute it too much.
I doubt the OFC nations would want it either. The revenue created probably wouldn’t be significantly more than what they already operate on. Plus, unlike us, they have their competitive balance, in that for the most part they are pretty well matched, bar the smallest four, so they don’t need to look elsewhere for meaningful matches. It also damages their World Cup hopes, they currently get 2 spots at youth WCs, and if they persist with a one-off final for WC qualification, then all it takes is a perfect storm of inhospitable tropical climate, NZ having a few key players out, and a dogged performance and they are at the World Cup. In any Asian comp they wouldn’t stand for one-off matches like that, so their chances would drop massively.
Either way, you need an exceptional circumstance for anything to instigate a change. An OFC team losing by double digits at a World Cup, a complete falling out of relations between East and West Asia etc, point is, I wouldn’t hold your breath.