First, let's talk about Gibbs's talent. While he didn't play much this year, there were reasons for optimism. Gibbs showed a savvy at times with the ball, and showcased the ability to shoot the ball, as evidenced by his strong percentages: .453 on field goals, .371 on three pointers and .773 on free throws. And while it can be dangerous to make generalizations between family members, it can be noted that his brother Ashton Gibbs rarely played as a freshman before exploding as a sophomore.
But unlike Ashton, Sterling probably wasn't going to get the chance to showcase that talent next year. Ashton Gibbs saw his minutes jump from 10.7 per game to 34.6 minutes per game. Sterling seeing that kind of boost simply wasn't realistic, and when Texas added both Javan Felix and, recently, a developmental point guard in DeMarcus Holland, there simply wasn't much time at the position.
In fact, it's probably Holland that Gibbs's departure affects the most. Felix was going to see the floor for plenty of minutes next year because 1) he's a polished floor leader who can run a team and 2) he can shoot, meaning that he could even fit into some packages alongside starting point guard Myck Kabongo. But there will be room for a point guard to grab, say, 5-10 minutes per game, and potentially up to 15 minutes on a great night. That would have probably been the province of Gibbs had he returned, but instead it allows Holland, a combo guard that the Longhorns aim to develop as a long-term point guard, to see more time at the position. And the fact that Holland can also play at the two will help him see more playing time.
So while it's a shame that Gibbs didn't get the chance that his brother did, either in terms of minutes or shots, his move isn't really a negative for either party. Gibbs gets to go somewhere where he'll get more of a chance to develop, while Texas gets more developmental time for freshmen Felix and Holland.