At present SkyWcs is a subclass of Transform<Point2Endpoint, SpherePointEndpoint> and this means that pixelToSky transforms to SpherePoint. However SkyWcs is always normalized to ICRS and so pixelToSky should probably produce IcrsCoord.
The simplest way to change this is to change SpherePointEndpoint to IcrsCoordEndpoint. One obvious alternative is to keep both and change the endpoint class SkyWcs uses. However, we have no identified need for Transform to transform to SpherePoint (nor IcrsCoord except as a base class for SkyWcs). Furthermore if we have N Endpoint classes then we instantiate N^2 Transform classes. So I propose to simply rename for now.