Well that's the problem - a lot of it is really just shifting from pile A to pile B.
This is actually a really good discussion. How would you design a system that is fair, honors free speech and still controls "undue" influence. Not sure I have an answer, but I think that ultimately it needs to all come from the campaign - not third parties.
I don't think limiting contributions work (they just get broken up and funneled through individuals). If not for that, I would be interested in requiring registration for all donors contributing more than $500 or so - but again, that's easy to skirt.
I'm not opposed to a spending limit, but I don't know how to get to that reasonably. And I would love to see all sitting representatives have a set annual travel allowance that they are able to spend to run normal business, and anything beyond that must be paid for by their re-election committee. (That may be in place already, but I doubt it's enforced with much vigilance.)