Ness' dair just doesn't do anything right these days. It's terrible at spiking because it's got an incredibly picky hitbox (who's idea was it to make it PSI based!?), and it's nto even that strong anymore. By "that strong" I meant like, not strong at all. I swear, every other real meteor I've seen is stronger than it. Falcon's, ROB's, Ganon's, Yoshi's, Mario's, it's just insulting. If you sweetspot it on the ground against someone, it doesn't lift them until like 30% or something stupid like that. In Brawl it lifted at 0%.
In addition to that, it's still slow as balls, got some super lag added to it, and can't combo for crap. So we have a move that's slow to start up, slow to end, bad for spiking, bad for combos, and has bad range. This move literally does nothing useful now. Shame, because it was one of my favorite dairs in Brawl. Now it's one of the worst.
Use it for PKF and air dodge cancelling, pretty much nothing else.
Flash is fun to use sometimes, I wouldn't put it quite in the same league as dair though. It's at least powerful, and doesn't leave you as open as people think it does.