Another opponent of the Comcast/TW Cable deal posted comments with the FCC before the deadline, but this one had more specific complaints. ArsTechnica has a nice article detailing CenturyLink's claims that Comcast has been throwing up roadblocks to stop them from entering the video business, and that letting them get bigger would just create even more opportunities to do it.
According to CenturyLink, whenever they seek video franchise rights within Comcast territory, Comcast's lawyers try to get the local government to demand that CenturyLink promise to go everywhere. In other words, Comcast wants to raise the bar for CenturyLink and not let them cherry pick their way to a profitable entry into the market that would then become more competitive (i.e. unprofitable) for Comcast. Or, if you prefer the other side, Comcast is just worried about the poor people.
If you prefer the outsiders viewpoint, it all sure sounds like a nice way to keep the vast legal teams of two giants busy fighting each other and not squeezing the little guy. I mean, it's hard to get all worked up about an ILEC getting its local regulatory toes stepped on, especially when it's clear that their complaint is just one more chess piece in that game. Even if they are absolutely right.
There are two main classifications of opponents to big mergers. There are the guys who hate anything that makes a big corporate entity bigger. And there are the guys who want leverage in some other pending dispute. CenturyLink, is the latter, it sees a chance to make Comcast back off. Unlike the more idealistic wing, they might manage to get what they want too. And unlike the idealists, they probably have an actual case.
But what CenturyLink wants is not to stop the deal but to use Comcast's desire to get the deal done against them. Whether the deal goes through or not isn't really the question, it's whether they can speed their own entry into the video markets they seek. But that's not a bad thing for competition either.