I don't completely understand the research. What do you mean by immediately following release? Are you talking about the deceleration?
The main problem with your conclusion that arm strength is more imporant is that the core is the "base" of your arm, and your legs are the "base" of the core. Your strength in your arm is useless if you don't have a firm foundation going all the way to the ground.
The bottom line is that you are limited by your weakest point. If your weakest point is your arms, then your arms will hold you back. If your weakest point is your core, then it wil hold you back. The same for your legs. Any point between the ground and your fingertips will affect performance and velocity.
Another question I would have is what does arm strength mean. Are you talking about doing curls, benching, or a more broad sense of the words arm strength?
I haven't seen this research, and I would love to, but the limited information given does not mean that arm strength is more important than core or leg strength.