that didn't get a ton of playing time last season. I think this stuff happens all the time. Many athletes aren't patient, aren't putting in the time to move up (see Steve Young), don't like the situation, or have other opportunities.
I agree that I'd like the top players to stay on the team (Mika, Bernard, Vaka....), but every team loses players for various reasons. I'd be very sad if Bryant and Childs decide to leave, but unfortunately, that is part of college sports now. One way to encourage players to stay is for fans to be less critical and more grateful of the players and coaches that have decided to be at BYU.