He's pressure/rushdown IMO.
He has neutral and can play a footsie and spacing game, but most of the great Necalli's I watch know how to pressure. One of the difference in the meh and the great Necalli's though is knowing how to play a slower, neutral centric game and space correctly, using his groundpound to check and punish certain things, etc, then transfer in to his pressure. He doesnt have a ton of range either, so knowing when/how to approach, etc.
Im certainly no expert, but I mained him for a while in s1, though most of my post is based on observation than my own play, because Im shit.
Also, for whatever its worth, I think Necalli is an incredibly good character that can monkey-stomp just about anyone, but is also very well balanced. He's top tier, I put him around Karin.
Not jumping in to the Shazzy/Rushdown argument, but I do hope Ryu gets some love in the patch this month. I really enjoyed playing him when I was trying to suffer through ranked and was using him earlier in the season, and I wouldn't mind picking him up as a secondary to Karin for when I feel like playing a different kind neutral... But me being me, I only want to play A+ characters because Im whats wrong with the world.