Joburg was/is a pretty well run, fairly corruption free Metro. Parks Tau did not do a bad job. But due to collective responsibility, he had to fall as well.
Mashaba will do well, but do not expect massive improvements. In NMB and Tshwane however...
Wow... are you for real? If the new council does a proper investigation / audit about awarded tenders you will find corruption and patronage everywhere. The CoJ billing system is a good start - there are quite a few MyBB peeps here who worked on the project and can attest what happened as soon as IBM was appointed and what followed afterwards.
Remember "Ecomobility month"? - insiders have mentioned a deluge of kick-backs from overseas companies. Parks Tau never did a proper job - he was hands-off and was more the PR person than anything else. In his defense (but not excusable as he should have gotten involved) - most of the the issues originate from the departmental executives.
Look across the CoJ departments and you will notice that basic/essential services are in shambles: JMPD, Pikitup, CoJ Water, emergency services, CoJ billing, JRA. TBH, the ANC has set the bar so low, that the DA/EFF just need to fix one pothole/traffic-light within 3 days and we will call it 1st-class-city-service.
I think the biggest challenge will be to provide essential services to the vast unserviced population and at some point in time actually bill for it. A huge issue, as the ANC has created a generation of people relying on handouts and freebies. I am pretty sure that for the middle-class the next two years will be really tough as we will have to pay up for all the mistakes been made in the last 20 years.
I am still not convinced that the DA/EFF is the silver-bullet to everything. Let's not forget that the very same DA councillors sat in those CoJ billing and eToll presentations and for some reason could not be bothered/comprehend the economical consequences those projects would great for generations to come (hell, they could not even be bothered to inform the public about it properly).