I agree with you. They have good centers already and if we see the performances of Looney and McGee this year's playoffs, they have stepped up and they contributed much in their team.
I hope they will not trade their all star caliber players for other players because they are a solid team already. Maybe they can trade some of their bench player but not the starters.
Honestly these days, teams are not relying anymore to Center position as there are players who can adopt multiple roles. Best examples are Draymond Green of Golden State Warriors. He is literally a power forward but acting as Center. Kevin Durant, for obvious role. LeBron James of Cavaliers, literally can play all roles. Kevin Love of Cavaliers too, acting as a center. Boston Celtics' Al Horford and as you see Celtics are playing without a center sometimes but still deadly on court. Other teams as well even the average ones.
Ok turning back to GSW, don't worry their starters are commited to the team for at least I think 3 to 4 seasons because other started just opened up another eligibility in their contract meaning their salary will not be their usual salary because they unlock some of the requirements. They can offer for that "if necessary". Why "if necessary", well kind long statement again so I will just end up here.
