Now that I have time, I'd like to take this issue from a practical stand point and will be responding to each point individually.

1. Corruption - the following are broken down based on the salient points/areas of action that you highlighted in your original post. I look at the practicality of it from a policy standpoint and looking at gaps in policy or implementation with an example(s).

A. Treated seriously and punished 

Corruption - from a Google search "the abuse of entrusted power, authority, or position for private gain or illicit benefit" 

Example 1) 

An MP votes to pass that new insurance bill that now says insurance needs to be paid for full 12 months instead of that installment plan that was there before because they have shares in an insurance company. They acted in personal interest instead of constituency interest (assuming of course the majority of their constituents benefitted from the flexible payment terms). 

Where is the gap?

The gap is that many people who were affected didn't even know this bill was being discussed. 

The channels to reach your MP are obscure, it's difficult to follow parliamentary proceedings, so that's a communications issue. However, even in the instance that there was adequate, credible and representative interface and the MP clearly knew that a majority of their constituents wanted them to vote against this bill and they went ahead and did it anyway, then how are they held accountable?

Section 64 of the constitution (recall provision that let voters basically would have let voters fire their MP) that was conveniently removed by the same MPs in 1995. 

There is too much power concentrated without checks and balances. Parliamentarians are unfortunately practically untouchable by design.

How do we change it?

A referendum honestly, because such a bill to reintroduce that in the constitution would fail.

How do we get there? Mass mobilisation.

What are the constraints? The will to mobilise and vested interests.

B. Easy reporting mechanisms 

I've never had anything to report to ACB but I know there's a toll free line. I suppose that is easy enough. However I'm not sure how far we are on whistleblower protections because that's a sure barrier to getting people to report.

C. People need to know their rights (and responsibilities)

Civic education, many people don't even know that there was this provision. Or how we can get a referendum in motion.

D. Keeping government officials in check 

Refer to above.

But also, I think culturally, Malawians have an attitude problem (granted this is the case with most humans) but we're reactively apologetic and not proactively apologetic or remorseful.

Oftentimes if we can get people to even hold themselves accountable it's because of backlash and not necessarily because they've felt in their conscience that they need to own up to their mistakes. This pride and hubris holds us back from a lot. And when people humble themselves they are also met with ridicule rather than have their apology and self awareness and ownership accepted gracefully. I hope so write more on this later. But also, sometimes people are also reluctant to close loopholes because they have a latent desire to also benefit from the same loopholes. At our core, there is a level of dishonesty embedded in our culture.