There is a lot more to shooting than just percentages, I will certainly agree with you on that, but for time's sake, % is quick and easy. I never played college ball, but I did play in high school and the only thing I was ever good at was shooting, and I used to be really good. I naturally gravitate towards liking shooters more than any other types of players, so I critique the hell out of them. For a 7-1 individual, Porzingis has solid form. Again, we don't need him to be a 7-1 version of Ray Allen, but even if he is at ~42% to 45% from mid-range, he would be enough of a threat that his defender couldn't cheat off of him. I will say this, I am more confident in Porzingis's ability to become a good shooter (for a big man) than I am of WCS for the reason you already said, the style of play in Europe. In regards to Kidd, he definitely improved drastically and now he is in the top 6-8 all time in threes made. Go figure. Ibaka is certainly an exception, but perhaps it was something he was decent in to begin with and never allowed to really use it.
The thought of a 7-1 big man who can shoot the mid-range at a respectable clip, be a weak side shot blocker, and be able to drive hard to the hole definitely deserves heavy consideration.