I am actually doing just this. I have been coached for several years but I am finiding that I am not getting enough personalization; my coach (regardless of how many times I tell him) doesnt seem to get my schedule right. Moreover, it seems like I am getting whatever the rest of his clients get, which drives me crazy. The progression and phases also doesnt seem logical (if he even thinks about it). I am a coach as well so maybe I am just frustrated that I am not getting the same level of attention and detail that I provide so I might as well coach myself. I also know my schedule so can schedule things based on what I know to be my low stress work days or my good days for training. I also like the autonomy.
Anyway, I am taking matters into my own hands. I am using the TR plan builder for the bike but modifying the swim and run and adding in strength of course. I know what i need to do in those so disciplines so I can take the alloted time that TR gives me and make it work roughly.
It will be a smooth transition I think.