Well it depends : you can easily slip into a "tyranny of the majority" setup where the parties in power don't need to accommodate the needs of the minority. Also if your regime is optimized for solving minor issues, it will have a hard time when there are important ones.

In general, there is no silver bullet, and as Solon (creator of the first constitution in the Antiquity) put it, each country will need a custom regime to fit its specific culture and society.