You know how the Spurs were way far ahead of everyone when it came to evaluating international talent? Red was doing that with homegrown players -- check out the Russell trade sometime - the other GM hadn't even seen Russell play when he traded him.
Yeah, unfortunately these days rim protectors "who fight to the end" on defense don't get undervalued. There's no market inefficiency there to exploit, as far as I can see. The only way to acquire a player like that without spending plenty of money and giving up ample assets is to trade for a guy who hasn't yet developed, or has been a backup so far in his career, and hope he can blossom.
That's what Morey did in trading for Asik, and it's mostly worked out for the Rockets, although they had to pay Asik a lot to do it. The only player I can think of who maybe fits this model now is Bismack Biyombo, who may develop into an (offensively challenged) rim protector, but is currently playing short minutes backing up Big Al in Charlotte.
Otherwise, the Celtics could kick the tires on Sanders or Asik and see if the price is right. Maybe one of those guys could become consistent and reliable here, though I'd be concerned about injuries and off-court stuff in both cases.
I'm not wild about trying to draft those players, unless it's a can't-miss kind of talent like Duncan or Davis. Maybe Embiid is that -- I don't know. But the "hit rate" versus the "bust rate" on athletic shot blockers seems to be pretty bad, and you have to draft them high.
I wouldn't mind Ainge using a pick in the middle or toward the end of the first round hoping to get a "hit" on that sort of guy. Cauley-Stein comes to mind.