1) A flat curve by July 2018 if the flattening trajectory continues (green lines);
2)A flat curve by Nov 2018 if we plot the trajectory from the recent steepening of the curve (red lines).
Also, Libor-OIS is still wide. One can argue Libor-OIS is structural in nature largely due to repatriation, BEAT tax and Tbill supply which can be attributed to Q1 and maybe Q2. Hence markets haven't really reacted and while L-OIS has gone wider, XCCY basis have tightened (JPYUSD, EURUSD and CADUSD).
If however, Libor-OIS continues to stay wide after Q2 then I predict the market will likely begin to see problems as the cost of funding trillions of dollars of products tied to Libor goes higher - a shift from a structurally driven increase in Libor-OIS to a credit/liquidity driven problem, the latter is going to be a big problem...