Being based in New Zealand most of the flights I take are long haul (10hrs+). The economy class with Air New Zealand is pretty good. Free wifi, modern screen with lots of entertainment, great food & service all included. It would be a lot better if there was ~25% more space. I would be ok with removing the other two classes, business & premium economy, to make room for everyone. It might not have to cost that much more than economy and would be cheaper than premium economy.

e.g. the layout of the plane we flew in for the NZ to Texas 14hr flight. If the whole plane's layout was XX-XXXX-XX and perhaps the middle seats were angled towards the aisle in pairs, e.g. XX-LLRR-XX, then that could be cool. Having only 2 seats by the window instead of 3 means if you're travelling with a partner then it's less likely for your group to be blocked from the aisle by a stranger or have to get up to let a stranger out of their seat. This can be an issue for long haul flights when people are sleeping and someone needs to use the bathroom.