It is only "radical" as a notion because they are in power - we wouldn't bat an eye at banning gang members from high trust jobs even if they were never convicted of anything - just being part of an organization party to such crimes makes them unworthy of the priveledge. So why treat this bad apple orchard any differently?
1. Expand the CCRB[1], both in number of civilian investigators and their authority to pursue investigations without interference from the mayor/city council/police commissioner. A line has to be drawn somewhere in terms of power granted to an independent review board, but I don't think we've even approached that line yet.
2. Change city/state law to prevent police misconduct settlements from coming out of city coffers. The public shouldn't have to pay twice (or three times, depending on how you look at it) for crimes perpetrated by the police. Settlements should come out of NYC PBA funds, insurance, or some other source that disincentivizes the force as a whole from covering for "bad apples."
[1]: https://en.wikipedia.org/wiki/Civilian_Complaint_Review_Boar...
1. https://www.nyclu.org/en/stop-and-frisk-facts