Finding solutions depend on how you define the problem. If the current mess at the IRS is truly a case of civil servants or elected politicians infringing on the free speech of specific political groups, that’s a problem for law enforcement and the courts. So far, what appears to have been demonstrated is incompetence and mismanagement, not crimes.
We should close the gaping hole in the current oversight system that allows campaign donors to funnel money anonymously through C4s. Unless we do so, the rest of the campaign finance system will continue to leak into C4s and the charitable element of the 501C section will continue to be tarnished by the "dark money" tone of the C4s. But let's be real, fixing C4s won't fix campaign finance or any of the problems with the larger nonprofit sector. The C4s as political money launderers are a symptom of larger problems with both campaign finance and the independent sector - fixing them is like the proverbial bandaid.