If say GM and Ford merged, I'd see your point. But the problem lies in that there is plenty of competition in the cellular market. There are literally over 180 cellular providers in the US -
source, so the angle the DOJ is taking in that it would create a monopoly simply doesn't fly in the face of the facts.
AT&T is overpriced and they pretty much do suck. I know someone who works in one of their call centers, so I have knowledge of how they run. I'm currently a T-Mobile customer and I could care less either way to be honest.
As for the 5,000 new jobs promise, I'm a little skeptical as well. There will be layoffs with a merger and how long would these 5,000 jobs remain in place? It is a shot at Obama and his administration and it will be used as campaign fodder for whoever his opponent ends up being. From my perspective, it looks more like the administration is siding with Verizon here more than anything. While both AT&T and Verizon have union employees, the Verizon employees have been on strike. I'm skeptical of the DOJ's angle here in addition to the promise to bring back 5,000 new jobs by AT&T.