I see the general attraction of being alert to new player builds, but what specific problem are we trying to solve? Do we really need to retouch our U21 formula? And how?
Generally, no, I don't think we need to screw around much with builds. Hey...me, you, Italy, Poland, Serbia, your grandma all know that tactics and players that it takes to compete at the elite U21 level. Not a ton of mystery there. The management challenge is having those players available and ready to play.
But to slightly contradict myself, at the same time there is some value to having different builds. The SF position has flexibility as far as what can be useful. A Yi can be used to give a different look and keep opponents in their toes. Personally, I think it would be interesting to see what a U21 level "Chinese LI guard" could do...if such a player could be viable. But I wouldn't like these kind of players to come
at the expense of the bread and butter players that will make us successful, but in addition to.