Honestly, NM is extremely HARD to play.
A lot of what you are saying isn't true.
His CE is extremely risky and isn't worth it for the damage output
His CE is risky, but 80 damage is more than worth it near the end of the round, where it is most threatening. Hell, smacking them with an early CE is great for making them shake in their boots later on. And like Captain Hook said, the threat of it is often times more deadly than the CE itself. Because of this, it is required to actually use it, if only a few times a set.
and his edge attacks aren't really that good.
If by "aren't really that good" you mean "aren't spammable and safe to use all the time" then you are correct. His BEs are absolutely fantastic for their intended purposes.
NM may seem to have good wall combos, but they are extremely hard to setup against experienced players.
They really aren't that hard to set up lol. Aga makes them afraid to step, 66K/3B makes them afraid to duck, and fca+g is there to keep them cornered to the wall. His wall pressure is completely top-notch and really makes him shine. Aga/66B spam in the corner is great for making your opponent piss themselves.
Yes, he does have a good backstep, but after the backstep nerf (making it unsafe to guard after stepping), spacing becomes risky/limited and at times guarding is a better option.
Most of the time, guarding is the better option than doing anything. This applies to everyone. If you don't take the occasional risk with NM, you aren't playing NM correctly. Backstepping is more than worth the risk, because the reward can be insane, and it was way too safe prepatch.
NM doesn't really have any good moves against downed opponents. GS B and
66B will whiff most of the time against experienced players. 1k against downed opponents is pretty much all you have.
GS B and 66B whiff because your opponent is rolling to the wrong side. His ground game is:
GS B to catch left rolls
44B to catch right rolls
1K to wake them up
66B for people playing dead
flapjacks for trolling
2a+b after certain knockdowns (a+g, 3b, 1a) will catch rollers AND people who play dead
GS K BE will pickup people if they attempt to roll after plenty of knockdowns too, like aga and 4KK
His ground game is a guessing game, but ranges from medium risk (GS B, 66B) to virtually no risk (44B, 1K). NM's oki is another of his strong points. You aren't looking to score big damage from oki, but you're looking to get them scared into rolling, getting them to stand and block GS B for guard damage or 66B for advantage AND guard damage, which will eventually let you get big damage.
The question's in the title:
What good moves did NM lose? What good moves did NM gain? Things to watch for? I had noticed that NM lost the 4B guard-break launcher he had in III, but that's all that really stood out.
NM has changed quite a bit from SC3 to SC5 I believe. From SC4 to SC5, however, he has remained basically the same. The only thing that has changed is the game itself, and it has changed to his favor. Otherwise, what to look out for hasn't changed; that mainly comes down to matchup knowledge.
NM is really good in SC5, and is perfectly viable in competitive play, much like most of the cast.
Also, is old 4B animation is now his UB. He lost his old UB animation though.