I think running a generic buffing horde army is one way of playing Nighthaunt. I'll probably play more aggressively with them though, as I always think of horde armies playing an attrition style game. With the abundance of movement options available I will likely go for an alpha strike, board control, or hammer and anvil. I'm sure they'll each be good for certain battleplans and against certain armies.
The lack of heavy hitters means you have to play strategically and attempt to enemy units and charge them with multiple units, which is something that can be done with the movement advantages we have.
It's interesting though, because to me Nighthaunt doesn't seem to be a an army that is beginner friendly for playstyle, which I thought would be the case with an army in a starter box.
I'm returning to the hobby after last playing WHFB and they remind me a bit of Dark Elves and Wood Elves from back then; where you had to really plan out each charge and move in order to full take advantage with synchronized charges.
As others mentioned, once it gets its buffs it's a pretty impressive model. It's a tank. Without the buffs, it still puts out a good deal of attacks that have frightful touch. It's also very mobile with up to a 14" move and the ability to run and charge once it reaches level 2 and the ability to retreat and charge once it hits level 4.
I think it's quite capable of being deployed with your main blob as an anvil, it can probably grab and hold objectives by itself, you can race it around with a unit of Hexwraiths, or you can deep strike it which could cause your opponent to over plan for it deep striking at them.
It's a pretty versatile piece, and I'd say a must take if you don't plan on taking Lady O (which I don't like to take named characters often, so I'll probably be rolling with the Coach in most of my games).