According to our sources, the Fujfilm X-E2s will feature the same 16MP X-TransII sensor of its predecessor, the X-E2.
Always according to FujiRumors sources, the most relevant changes/improvements compared to the X-E2 will be firmware based.
I hear you are scared now about your long rumored X-E2 Firmware update. Don’t worry. I have multiple confirmation from sources and even Fujifilm itself said that it will come in… mid-January. Just read this post.