I think that it depends on the player. I've carved a niche for myself as a 3rd and 4th book big band player, and I do so with the knowledge that my efforts on those books - the 4th book in particular - can help to determine whether the lead player has a good night or not. If I'm doing my job right, I'm playing in total support of that lead player, and that's not something to take lightly. It may not get the glory of the lead chair player, but make no mistake, it's not a task to take lightly, and needs to be approached with a similar amount of aggressiveness and confidence, because otherwise the lead player doesn't get the support that he or she needs. But that's big band. The concert band players who like to hang out on the 3rd cornet book - the ones who hedge behind the part and who you never actually hear - those are (IMO) folks who maybe should consider a different instrument. Yes, those parts are important too, and they can be approached in much the same way I approach my playing in a big band, but not everyone does - there are a whole lotta meek trumpet players out there, and to me, the attitude and the instrument are not a very good match.