There have just recently been quite a lot of speculations for why F.U.Z.E is going to be the next elite-reskinned character and mainly that was because of some "leaked" photos. Now here is the explanation for why he is actually going to be next - or at least glaz is.

Next character should be a German or Russian operator but we do have more elite reskinns for the defenders side than for the attackers side right now and the Russian and German operators are the viewest base-op-elite-skins and both defenders. But the gsg9 one has just recently been released and that makes it very likely for us to get a Russian attacker operator elite skin next!