Just a small hint of a rumor of an R1 will have me excited.
But, a 1DX Mark IV which has expanded AF capabilities through the OVF (ie, larger area AF sensor, eye detect) would have me ecstatic!
Even if a 1Dx IV were to materialize, it is two years too early. Although I doubt we will ever see a Mark IV.IDX Mark IV would only need a stacked sensor to get me excited.
Exposure-only IBIS would also be a big plus.