>Doesn't this syntax make argument-inspection un-necessary? If the dimensions parameter is specified, it means "set up a case 2 Node", otherwise it means to set up a simple "case 1" node.

I'm not sure it is a good idea to use the existence of the `dimensions` argument as a secret indicator of time.  If the user did something like
```python
a = nengo.Node(np.sin, dimensions=1)
b = nengo.Node(np.sin)
```
I think they would reasonably expect those two to do the same thing.  If we wanted to use parameters to distinguish the two cases, I think it would be better to just have an explicit `uses_time=True/False` (or `n_args`, which would be essentially the same thing).