Anderson is very good for a Big as he has high percentages and can shoot 3's. BUT, George is good and continuing to improve and is putting up fine numbers across all categories (and is expected to garner lots of minutes and be the primary scorer for the Pacers). It's not an EVEN trade; but as a commish, you have to look at the TOTALITY of the trade. Is the team giving up Anderson a better team than the one receiving him? Are they close? Does the team giving up Anderson have too many star big men and needs an SG/SF? No trade can be perfectly equal and while Anderson was straight stoooopid last year, the season rankings on these two, dependent upon your settings, is pretty close. If the team receiving Anderson is the worse of the two (not just in standings; but the team overall based upon the roster), I'd let the trade go through. If the team receiving Anderson in the trade is an already dominant team and this trade will make it that much better, then I'd strongly consider squashing it.
As a commish, I see my job as overseeing the LEAGUE'S overall health and parity for ALL TEAMS. Not just satisfying the whims/desires of individual managers. The is even MORE IMPERATIVE in keeper/dynasty leagues.