Well I think all builds should use 4.2 and 4.3 with options to disable it if your CPU doesn't support it. An option somewhere have been using Lectrode's SSE 4.3 builds with DX11 plugin been seeing 60 fps in all games with my i7 950 at 4.2 ghz there is nothing I can't accomplish with dolphin 30 fps in Hyrule Field feels good mang. I think all build should use it and am curious why they don't?
There is no SSE4.3 ,it never exist
SSE2 , SSE3 ,SSSE3 ,SSE4.1 and SSE4.2
and its not possible to implement such a option, because its a way how it gets compiled
just compile it yourself... problem gone
or wait 99% all all problems are caused by user behind the keyboard
ICC can compile optional code paths for multiple CPUs but the docs warn that it might hurt performance.
Dolphin already has runtime optimizations for sse4.2, sse4.1, ssse3, sse3 all built in which are automatically activated if it detects a cpu that supports them.