Thing is, you also need to send out matching salary, or realize that you're gonna have to give up rights to some combination of your free agents to make a deal like this. So for Nene, for example, you're not just trading two first round picks. You're trading two first round picks, Ray Allen and either Kevin Garnett or Jeff Green and Brandon Bass. So your roster is Rondo, Bradley, Pierce, KG and Nene with a bench of Johnson, Moore and Stiemsma (or sub in Bass for KG and add Green to the bench), with only a $2.5 million midlevel exception and minimum contracts left to build a team and no more youth. That's not a contender in the near future and there's little youth to build for the future around. And that $13 million annual salary for Nene is going to look worse and worse - he'll be 30 next year, is under contract for four more years and is already on the decline.
In theory, using the picks for a known player is a great idea. But to do so this summer, when you don't have a matching contract to include, means you're using cap space which means you're also renouncing rights to at least some of your free agents. So you're not adding on to what you have, you're starting over with Rondo, Pierce, Bradley, and this piece, while giving up some important chips for the future. Neither Nene (30 this summer) nor Scola (turns 32 at the end of this month) is a guy to build for the future around.