Your thread has contradicting statements. First, you don't have to be 5.0 to play with this frame. You could be 4.0, even 3.5 and hit pretty well with it. That's its charm, it's such an easy frame to use and the control is amazing. I think they just throw the NTRP level range as a racquet that is of "tour" level as of any company that produces as "pro" line. Secondly, club players are usually very good in between 4.5 - 5.5. There's probably more abundance of 5.0 club players that you'll find than 4.5, so I don't see how you would lump them into two DIFFERENT categories.
Your other statement of complaints about it are just from indvidual tastes, people complain that the pro staff line is "too stiff" does that mean that there's not a market group for them? No, because that would mean that the racquet is flawless. If someone is playing with a tweener say 10.6 and they pick it up, it's obviously going to feel heavier at 12.1 oz. It's more of what they're used to and you'll get a lot of that with more random people giving it a test drive seeing as how it's been hyped up a lot. People gave the K90 a lot of hype and a lot of people who aren't a good fit for the k90 had complaints of their own.
You're thread suggests that this racquet is for everyone, which it isn't. More so, no racquet fits that description. This racquet has qualities that appeal to individual tastes and styles in which a lot of people differ, the number of people demoing this racquet who are playing with say an aeropro drive for example are the ones who might be voicing their qualms of the differences that they might not be used to.