I very much doubt that Iggy would accommodate AI again the way he did before. The team is already pretty hard nosed, but clearly a team that also practice hard and works on execution, even if it does not always perfect it. Miller needs to handle the ball to be effective, something that just won't happen with AI around. As tk noted, AI is no longer a true force of nature, just a good scorer who can't defend anyone at SG or PG. Guys like Iggy, Thad, Speights and Lou all need more touches than they would ever get with AI. Brand at this point can anchor the D, has a more varied offensive game and is a hellacious rebounder. No, I would not make that switch/trade/whatever for this year or the future.
For the short term one might more reasonably ask if the whispered rumor of Brand for Rasheed Wallace would make more sense for the Sixers just for this year, than any move for Ai would be. Wallace, when motivated and healthy, does not need a lot of shots to be effective, plays very good D at both big spots and can hit the three. Not that I want to trade for him, but Wallace would be a much more suitable replacement for Brand this year tham AI would.