It would be absolutely fantastic if people would be rational about tech news. Tech people/netizens are starting to sound like my grandfather now. Every change is something to be feared.
It ain't paranoia if they really are out to get you.
Considering DD-WRT was mentioned by name as something that would explicitly be banned, yes, this is something to be feared. If the FCC was doing their job, the job of regulating transmitters in order to preserve the utility of the commons that is the electromagnetic spectrum, the job that someone else pointed out they've been doing for 80 years, then there would be no problem. But when the proposed rule is worded primarily for the purpose of enriching a tiny handful of corporations, and only tangentially justified by their actual mandate, we're going to start sounding a bit shrill about it.
Tired of how shrill Slashdot has become lately? Blame the problem. Regulatory capture, and ongoing attempts such as this to extend it. This is the new normal. So of course we're going to become suspicious of every change, and of course we're going to be shrill about every change, because even when it's not such a blatant attempt at profiteering as this one is, Occam's Razor leads us to the conclusion that it's just a more subtle attempt at profiteering at our expense that we haven't figured out yet. The expense not only of our pocketbooks, but also our freedom, specifically the freedom to do whatever the hell we want with our possessions.
The people running the FCC are people, but they are not just like me. Not in the least like me. The people running the FCC tell 300 million people what they can and can not do. I don't. They are not remotely like me. Therefore if I want to be suspicious of their motives, I damn well can be. Judging by past behavior, I damn well should be.
 And before the pedantic among us 'correct' me and tell me I don't have the freedom to do whatever the hell I want with my possessions, it was a rhetorical device. The previous paragraph acknowledging the problem of preserving the commons was your clue. I am perfectly well aware that this is a worthy and laudable goal, and if the number of cases of WiFi AP firmware modification resulting in out-of-spec radio performance that interferes with other uses of the spectrum ever rises above zero, the FCC might have a good reason to issue a new rule. But it still wouldn't be this rule.