I think that this will certainly change things, but not necessarily how you all are saying.
I don't believe we'll enter a situation where Scrooge McDuck tells a politician, "I'll give you $1 million if you vote this way", and then the politician votes that way. That's way to easy to track down via transparency sites.
What's going to happen is that you won't get as many "grass roots" candidates. Right now, a candidate for a US Rep seat will run about $1.3 million. No chump change. But, considering that the average House member represents roughly 710,000 people, that's only spending $2 per person to reach a voter. If more money is poured into races, then that cost could easily double, reaching $4-$5 per constituent. This will mean that only the main-est-of-stream candidates will be able to run, and will leave out long-shot, non-career-politician types of candidates.