I think the critical difference was that the Wakandan techs perceived Bucky as a person, so they built an arm that could primarily do things that people need. Rather than thinking of him as a weapon and building an arm that could primarily do things a weapon would need.
Plus, just from a technical standpoint: I think it would be relatively easy to test the raw strength of the arm while it's unattached--can the servos handle this much resistance, how many pounds of force can it deliver, etc. Whereas the finesse would depend more on its sensitivity in relaying outside stimuli and responding to Bucky's commands, so that needs to be tested on him.
Re: Wow!
I think the critical difference was that the Wakandan techs perceived Bucky as a person, so they built an arm that could primarily do things that people need. Rather than thinking of him as a weapon and building an arm that could primarily do things a weapon would need.
Plus, just from a technical standpoint: I think it would be relatively easy to test the raw strength of the arm while it's unattached--can the servos handle this much resistance, how many pounds of force can it deliver, etc. Whereas the finesse would depend more on its sensitivity in relaying outside stimuli and responding to Bucky's commands, so that needs to be tested on him.