Your question is more in tune with an individual, more anything. That’s my opinion anyway. The reason for my opinion is that, as a youngster goes up in age and classification (from what I’ve seen) each youngster brings a strong suit of one or the other - heat or control. Some even pull the trigger on both, but this is rare. For someone breaking into the high and college ranks, I’ve seen a more of who-ya-know, rather than what you can do. Now I know there are angry voices that say … nay… not on my club. But that’s another posting.
If you really want to answer that question, think of the age group and the muscular coordination and growth issues that compound the pitching experience. In that regard, I’ve seen 15 year old’s that burn all day long, and great command. But, that same individual that I had high hopes for at 18 (legal age a majority to talk to) still had heat - but command was if-ee, for the age and competitive level.
Pitching with heat for the age level of 13 - 15 - generally, is great, with control taking a back seat to the hopes of control coming around. (well, from the crowds I sat with.) By the time a pitcher who wants to stay with the game, and then some, by 18, control better be a given with heat being there when wanted/needed.