It is a bit of pity. A least non-sliced indexing should be able to work:

>>> import numpy as np
>>> a = np.arange(10)
>>> memoryview(a)[0]
0
>>> a = np.arange(10).reshape((2,5))
>>> a[0,1]
1
>>> memoryview(a)[0,1]
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
TypeError: memoryview: invalid slice key