Trump said today, in a speech in Gettysburg, PA, that if he becomes president, he will work to block this transaction because it consolidates too much power.
If you want to talk about a conflict of interest in presidential candidates, Hillary Clinton has received at least a combined $1,564,708 in political contributions from AT&T and Time Warner. Additionally, AT&T's senior executive Vice President James Cicconi has endorsed Clinton.
Trump has many more businesses than just real-estate and his content competes with the content factory that AT&T wishes to procure (Time Warner, not time warner Cable the ISP).
Though he's already had a run-in with TWC (not involved in this deal but I highly doubt that would matter much to Trump).
http://www.latimes.com/entertainment/gossip/lat-hh16-donald-...
Not everyone :D