It's not fair to company 2008 NW with 2018 DL -- not just physical things (lie flats, etc) or program (upgrades, redemption rates). I expect if there was no merger these things still would have changed. Maybe differently, but they would have changed ("Man, the NW iPhone app really sucked"
)
I do miss the KLM integration -- it has gotten better recently but still not as seamless as the "old days."
I also miss MEM -- easy to connect and some good BBQ while you waited. I expect some on the DL miss CVG.
I have yet to fly on a 787 but all my friends who have have raved about it (and they are in coach). So I can't say that is miss it but I miss having to opportunity to regularly fly on it.