does "legacy" cubemap mean it being phased out?

i see cubemap now appears under legacy option under create menu

does this mean six-texture cubemaps being phased out?

(should i be looking to use alternative spherical/cylindrical method?)

yes, it is preferred to create cubemaps using the Cubemap texture import type now:

48149-2015-06-13-234156.png

This way cubemap texture data can be compressed; edge fixups and glossy reflection convolution be performed; and HDR cubemaps are supported.

For more details please see the link:
http://docs.unity3d.com/Manual/class-Cubemap.html