Kettlebell Muscle is the simplest program to implement that you will ever see, and only requires one pair of bells. It's simple in the sense that there is absolutely no thinking or decision-making involved, after you decide what size bells to use in the first place. Every set, rep, and rest period is specified. You just show up and do the work. Like any other program, is does require that you have good technique in the exercises used.
KB Strong can be adapted more toward strength or hypertrophy, and for different exercises, such as C&P or C&FSQ. The One program is more of a conditioning program that can be combined with Strong or done on its own. Both programs only require one pair of bells that you can milk for a long time.
I looked up the two programs you mention, which look perfectly reasonable. One thing I don't like about the KettleBear program is that it has you doing a lot of C&Ps and then FSQs with the same bells. I'd prefer more cleans and front squats with heavier bells. The Prometheus program at least lets you use heavier bells for the FSQs. But then you need different sets of bells, which you said you wanted to avoid. Again, IMO, for hypertrophy, the money is going to be more in heavy C&FSQ, with presses as a supplement, not vice versa.
Aside from those programs, two of my favorite simple complexes originate, AFAIK, with Dan John. There are lots of ways to progress these. For hypertrophy, keep the rest periods relatively brief (2 minutes or less).
The first is the 213 "grad workout" complex (2 DCL, 1 DMP, 3 DFSQ). This one has a great ratio of pressing to cleaning and squatting, so you can use heavier bells and aren't too limited by having to get them overhead, since there is only one press in each set.
The second is the DCL & DFSQ ladder (1 DCL/1 DFSQ, 2 DCL/2 DFSQ, etc, without putting the bells down). This one you have to do to appreciate, and don't think your arms don't get enough work, especially as you progress the ladders higher.
