FWIW, my son has always had a worse year with a younger teacher. I tend to look at a new teacher and know early on how the year is going to go by whether the teacher has had kids or not. That might be a personality issue and not a gifted issue. Young teachers are not as experience, IMHO, with squirmy little boys who do not fit the educational mode as well. If a teacher has had a squirmy little boy of their own, or has taught long enough to have had quite a few in the classroom, then I know we are going to have a fairly good year. The younger teachers seem to do better with people-pleasers, which for me tends to be quiet little girls.
My DS8's best teacher so far was his K teacher who had had a gifted girl and an AD/HD boy of her own. She had quit her job as a real estate agent and gone back to school in her 40's to become a teacher. DS had her in her first year of full time teaching. She was a treasure!!
1st grade was a terrible year with a young, inexperienced teacher. She had been a intervention specialist before moving to 1st grade, and was truly gifted when working with slow learners. She had no understanding of HG+ kids. To make matters worse, the school decided to make an immersion classroom, where they grouped the very advanced kids with the very slow (Title 1) kids. That way the classroom could break into two sections when the reading specialist came in to help the slower kids. But the teacher found it necessary to go over everything many times, from directions for work to math concepts. Truly a nightmare year.
2nd grade was wonderful. DS had an experienced teacher who recognized that he was different and needed to be challenged. She could masterfully put differentiation into effect in her classroom and give DS material that covered more depth. She is the one who started the grade acceleration paperwork. Unfortunately, DS only had her for half of the year.
DS then had a male teacher for half of third due to a grade skip. He was great at understanding DS and his different style of learning and his need to keep something in his pocket (a lego figure usually) to fiddle with. He had been teaching for several years (6ish) but did not have kids of his own. I don't know if it was the lack of kids or inexperience on his part, but he had really never seen a kid like my son. He tried to give DS some extra work, but mostly just let him sit by himself and draw space battle cartoons after he had finished all of his required work. And although he understood him wonderfully in some respects, he did not understand how he needed to be challenged or some aspects of bullying and tattle-telling that went on in the classroom that made my son a target.
Well, this was longer than I had expected. I hope it helps some. I think matching the personality of your child to the personality of the teacher gives the best chance of success. But the more experienced a teacher is, the more likely that they can work around personality differences, as well as provide a challenging environment in the classroom.