One of the main advantages of liberalism is that it focuses on the betterment of society—social, political, economic and cultural growth, progress, and prosperity are essentially the main goals of liberalism. According to liberals and some political analysts, a liberal system is (or at least should be) the foundation of democracy, as liberalism as an ideology is built upon the concepts of liberty, freedom, equality, peace, and protection of and advocacy for human rights (the people benefit from the state, and the state benefits from the people).
Aside from sociopolitical stability, security, personal freedom, individuality, liberalism also promotes economic development, as well as equality of opportunity and freedom of enterprise.
On the other hand, critics argue that one of the disadvantages of liberalism is the people's dependence on the government. As a liberal government tends to be very involved in nearly all social, economic, and cultural spheres, then people expect the political leadership to excel in their jobs and to make sure that the people are safe and comfortable and that the society functions the way it's supposed to function. This is not an easy thing to do: the political structure is often prone to criticism, which might result with sociopolitical imbalance. Conservatives also argue that liberalism disregards the importance of traditional values and destabilizes the cultural sphere.
Radicalism is actually derived from liberalism, as it was a political movement that united the extreme left during the French revolution, and it is also the inspiration for the creation of the theory of social liberalism. While liberalism focused on individual liberty, radicalism focused both on liberty and equality.
The main advantage of radicalism is that it promotes sociopolitical reform. Radicals (be it the radical left or the radical right) argue that radicalism as an ideology encourages the people to challenge the system, especially if it fails to meet the individual needs of the people and the general needs of the community as a whole. Unfortunately, radicalism goes hand in hand with extremism; thus, a radical democracy can either be a Utopian or a Dystopian society.
In this context, extremism is the main disadvantage of radicalism; extreme thought is either too ideal or far from ideal, which is why it's often accompanied by violence and oppression. Radicalism may promote difference as a philosophical and political concept; however, it's unclear what that difference is. While it might mean acceptance and tolerance of diversity, it can also mean the complete opposite.
Some argue that radicalized societies accept terrorism and extremist violence, which usually appears as a consequence of the people's frustration with the local socioeconomic and political climate and structure. This anger and frustration with the system and the need for a fundamental societal change is essentially the main reason why many people tend to have radical views and opinions.