Lessig has in the past advocated for a variety of solutions that don't involve restricting speech, or organization. One option is to give each voter a $50 voucher that they can give to whatever political organization they wish. This retains all the of the functions of politics that we see today, but restores the dependence of politicians on the people, rather than the few who give most of the political money today.
I dunno how much it cost exactly but I'm sure that making and distributing "Hillary: The Movie" cost a lot more than 50 bucks. Limiting individuals to that total is a restriction on their speech.
Now, maybe that's a restriction that we want to impose but it's disingenuous to say it's not a restriction.
I'm less concerned about campaign finance reform in general as communications tools get better; producing a great viral video is something a person with "no money" can do and contribute to a campaign, whereas running $10mm of TV ads requires...$10mm.