The extreme case which you want to avoid is "politicians" (dictators) desperately clinging to power, because they did things that would get them killed if they ever lost their power, which is a vicious cycle.
In many of the contemporary cultures (e.g., the post-Alexander greek kingdoms), being toppled from the heights of power would result in exile, imprisonment, or worse; in the republic, you could lose a battle as a general or step down from being consul and still lead a peaceful life afterwards.
One could argue that the change in this situation in the late republic directly resulted in it's downfall--Caesar crossed the Rubicon because he feared prosecution and imprisonment by his opponents once he lost his proconsular immunity.
I like the swiss model more where one party never gets full power, even if it means societal changes take more time to happen[1], it seems less risky to me as there is never one power grab whose decision can influence the next election by stuff like redistricting, puting clearly leaning judges to federal court, etc.
[1] famous example is the women right to vote in the general election happened in 1971 which is quite shameful