Garliv,
Parliamentary for me has these merits
1. Equity and dilution of tyranny. The Kikuyu-Kalenjin monopoly is a major source of bad feelings of inequality among other groups not just Luos. Even in the imperial US you have the electoral college to manage tyranny. California and New York are Kikuyu and Kalenjin.
2. Accountability - separation of the ceremonial state from the daily government. Look at the UK where Boris Johnson has to account for his Brexit plans inch by inch. In Kenya lazy Kibaki signed off an island to a foreigner bila maswali. Even this harassment you are complaining about - Uhuru or Matiang'i are unaccoutable due to the opaqueness and impunity of the president. Uhuru talks to the media, MPs or judges when he chooses. Brat can't even be grilled. He alters bills and needs supermajority to overule him. Peolple are accused of disrespecting him before the lynching. Imperial president is impunity 101. National policy should be properly debated and that should not be the preserve of State House. PM is grillable and challengeable. He does not veto laws and such extra-legal powers. He is accountable.
3. UK is not the only successful parliamentary system. 95% of the first world is parliamentary. UK, Canada, Germany, Japan, Aussie, NZ, Israel, etc. The US has anti-tyranny check.
4. Shortcomings can be fixed. Leader of the majority party or coalition is the automatic PM so no need for bribes. Jubilee would be Uhuru and to remove him Ruto crew would have to quit the party. You can't impeach PM but the entire party. Study the UK - I smell some ignorance.
We would need good party discipline.
Regardless of the nuances - fixed terms, party elections, etc - equity and accountability are ensured.