Personally I think ideal set up is a system which grants quite a of power to a small handful of people, but makes it very easy for those people to be removed. This is typically the model that works best in business and other cooperative pursuits anyway.
Throwing more people in the room with different opinions will ensure significant decisions can almost never made. Any policy too far to the right or too far to left will be watered down. The result is that you'll be led by centrists who can't really change anything and anything they do change will be disliked by everyone.
I think ideally you want a CEO type leader of a country who has a lot of executive power, but that leader has a board who provides oversight, then ultimately the public are all shareholders who collectively hold the company and it's leaders to account.
I'd argue generally speaking we want to grant more power to our leaders than we do today, but make them much easier to remove and have a well design constitution so certain things are legally impossible in the same way a CEO can't just decide they now have 100% voting rights and no longer need to listen to share holders.
The solution to a bad CEO isn't to have 10 CEOs. The solution is for the shareholders to boot them for a better CEO.
Because congress and senate in America are soooo active ...