I suppose the question eventually becomes: do we want these patches, or do we want to do this differently? E.g. if our ultimate goal is "get rid of the state table entirely", perhaps it makes sense to just pull state handlers out of the state table one at a time, and basically turn extension selection into a conditional while doing so. The idea of this patch is to do that in two steps instead of one, but it does have the disadvantage that it hypothetically makes performance worse in the meantime.
The performance impact doesn't seem too concerning at first sight, but it never hurts to run some benchmarks when making these kinds of changes...
As an aside, note that some of these state handlers end up being somewhat poorly named by these changes. E.g., glsl_vertex_pipe_texmatrix_np2() doesn't really cover the purpose of the function if we're making it the general STATE_SAMPLER handler for glsl_vertex_pipe_vp_states[].