Honda needs at least one more year to improve the PU to a competitive level, otherwise I don't understand why they've agreed on rescinding the contract with McLaren. There is no management that can justify a decision to move to a smaller team, with smaller budget for chassis and aero development and slower drivers, if they believe their PU in 2018 will be competitive. Horner comment that Honda will work in peace for a year at TR, without a need to perform at highest level, just confirms my suspicion.
I hope Honda had recognized the problems and have a plan in place to improve. Godspeed.