Actually, no, he does not have to be "Semitic" as a large portion of the population were in that period what are today referred to as high noble Arabs. Tall, athletic, muscular. Think Omar Sharif. Much like what we see in the man in the Shroud who is variously calculated to be 5' 10" to 5' 10 1/2" tall, hardly out of the normal range. They accounted for approximately 40% of the Jewish population of Israel in the 1st Century.
A census of 1st Century male skeletons in Jerusalem cemeteries found the average male stature was 5' 8 1/8" tall. The average height of men in America today is 5' 8 3/8", a quarter inch taller. Strangely, the average height of the Roman conquerors in the 1st century was only 5' 6".
Remember, we are talking about the single most investigated and studied historical object in history! You really don't think a claim that it can't be real because it doesn't look Semitic would NOT have been investigated by now, do you? Prior to Secondo Pia's first photographs of the Shroud in 1898, the only research being done was essentially historical and iconographic.
I’m sure you have seen the History Channel show from a year or so ago. Amazing work! Here is Part 6 where they reveal the 3D image from their data analysis.
I never said one word about height. I wrote of facial features only. Do the representations of Jesus make you think he was Arab? The representations i have seen show a very light skinned man, a very unlikely scenario.