To Judge Moi appreciate the historical and geopolitical realities of his day.
1. I don't know whether any other African country had attempted or managed to have multipartism. Therefore he would have been hesitant and without much example to enumerate.
2. Economically Africa economy was designed to serve the colonial masters and superpower, US. It is still is but then it was worse. Therefore he wouldn't have been able to change much. Just like Kenyatta had adopted economic model dictated or left by Britain. Besides there was very little alternative knowledge/education to implement anything else.
3. For corruption, Kenyatta was not much difference. A professor of Anthropology at Nairobi University gave a theory about this TKK (toa kitu kidogo). It goes like this: in African culture (most of them anyway) when one pay a visit to someone either for some service, request or whatever first they are welcomed with "chai" and something to "chase away hunger.." then afterwards they deal with the "real issue/agenda" of the meeting. In a commercialised society TKK takes place of that tradition.
When "chief" or "village Richman" or "senior mzee" invited people to his home or to a gathering he had to show/flaunt his wealth and influence. Translated into modern commercialised society the "big men" have to give handouts, offer some favours, donate cash here and there in a way to flaunt and be recognised.
And this still works today. An honest hard working civil servant who relies on his salary may not achieve much in terms of big houses or cars or anything. But among "his people" and in his "village" he is dismissed as a useless fella who "had big position" and did "nothing with it" and "didn't even help his people..." "huyo mtu ni bure kabisaa.."
My point this corruption this and this TKK is deeply ingrained that we need to study ourselves. We can keep "fighting corruption" from dawn to dusk with such attitudes the fight may never be worn. That's why even civil servants at EACC or DPP would need "mshirikiane" so as "msaidiane..."
4. Finally, remember cold war era. It shaped a lot of what African leaders did or did not do. And it shaped Africa's destiny. In politics and economics.
Then neoliberal economic theory that was forced onto Kenya didn't help. Indeed i would argue it's the worst thing ever!
Koreans didn't follow IMF/WB to get where they are despite what some Western/Kenyan sources claim.
Moi's brute and barbarism is actually blamed on Raila who triggered him like an automaton. If you weigh the good and the bad of Moi he comes up pretty short. I have argued here before that he invented "TKK" and democratised corruption. The economy really tanked under Moi. The lost opportunity - when people contrast the Asian Tigers - Moi squandered Kenya's golden years.
Moi ERROR is Kenya's dark age.