As a HS club coach I prefer holdbacks to non holdbacks. The extra year is the difference between winning and losing in Club and their HS team. For you that dont like it, well that's your issue as majority of coaches want the older players.
Doubt this is a coach- As a coach, I want players that can play and compete- regardless of color, national origin, and yes AGE- Age is a number that tells me NOTHING. I have seen too many holdbacks that end up being slightly larger, but a pain in the rear, immature and bad fundamentals, that end up crumbling on the sideline because they don't know how to face adversity when they face kids their own size or skill- this holdback advantage starts to even out the deeper you get into HS.
In fact, two equal players or even "close", who are say 1-1.5 years apart, I will take the younger player, as he has more room to grow (and I am not talking physically).