My personal experience is different. I received an excellent post-tryout written feedback from one of the coaches who took part in evaluation, with specifics on the areas for improvements. I was pleasantly surprised.
And contrary to a reasonable expectation, players very rarely get an individual attention, coaching or corrections during the large group tune-ups. Tune-ups are not designed for skills improvement. The objective and benefits of tune up is to prepare the player for the structure, content, pace, and types of drills that will be used in tryouts for the respective age bracket.
There are so many kids participating in large group tune-ups, there is simply no time for coaches to do corrections. And if the kid is lucky to be corrected at all, it is not nearly enough to result in a noticeable skills improvement. Therefore, the effectiveness and benefits of a large group tune-up sessions is about the same as tryouts.
Just count how many times coaches individually corrected your kid in next tune-up.