Yes, I also find the TR workout library to be very valuable. The way I use it, though, might be slightly different:
My interval training is focused on building fatigue resistance through doing progressive Time-in-Zone (TiZ) intervals, or more specifically, for intervals at lactate threshold and below (e.g. sweet spot, threshold, over/unders). So as I continue up the time ladder within each type of interval, I search for workouts that meet the progression, such as going from a 30 min threshold workout of 3x10 to a 36min one of 3x12. I then import the workout into Workout Creator and make modifications I feel appropriate (warmup, intensity level progression, rest interval, cool down). The dual combo of the workout library and WorkoutCreator is great!
Not to be greedy , but I am looking forward to improved workout library search and WCv2.