I don't think the team needs to be blown up in order for the Spurs to become successful once again. Ironically, the team that swept us this year is proof of that. The Suns didn't even make the playoffs last season, and now look at them. All with no major additions (but admittedly, one major addition by subtraction in the jettisoning of Shaq).
This being said, it was painful to see Gentry expose Duncan towards the end of the series. The Suns went right for the player with no lateral movement, Duncan, and scored at will. What is going to stop the Suns or other teams from doing this to us in the future? Furthermore, if Duncan looked this slow after playing the least amount of regular season minutes in his career, how much slower will he look next season?
The Spurs need another really good big man. They need him so we can hide Duncan from strategies such as the Suns, and we need a guy that can be the man with the four littles when Pop goes small and Duncan is on the bench. I dont know that Tiaggo Splitter is the answer here.
For this reason, the Spurs should consider trading Parker. The key word here is "consider". Big men do not fall from trees, but Parker is not chopped liver when it comes to bargaining pieces.
Yes, San Antonio would have a big hole at the point guard spot, but I believe the current chasm at the big man spot is a bigger problem.