Part of the difficulty of this question is that Baathist philosophy is not commonly available. According to Wikipedia, Zaki-al-Arsuzi is one of the founding theorists of Baathism through his book, "The Genius of Arabic in its Tongue." Although I couldn't find an English copy of this book, a pair of scholars summarized al-Arsuzi's philosophy here. I'll base my answer on their synopsis.
Nationalism
First, Baathism is a form of Arabic nationalism. Much of al-Arsuzi's work is dedicated to exploring the unique cultural and historical positions of Arabs (especially through their language). The expression of a culture is in its community or government. Therefore, we would expect every culture to have their standards for society. In particular, Arabs should have a kind of government which is a reflection of their own unique culture.
This is similar to other forms of nationalism, which also focus on their unique social contexts (for example, Fascism reflects Italian cultural history and Juche reflects the Koreans'). It is different than Marxism, which purports to be universal (that is - it can be applied equally well everywhere).
Role of Culture
Many kinds of political thought have a "substructure" - some element that is fundamental to the political order. Most elements of theory can be reduced down to the substructure.
In al-Arsuzi's view, the substructure is Arabic culture. Culture is the predominant driver of how the government should work and how society should be organized. It's somewhat interesting that he doesn't place much emphasis on Islam. In fact, he anticipates a re-birth (ba'ath) of pre-Islamic Arabic culture. Islam is the product of Arabic civilization and should be retained in society. Islam, like many other things, is a secondary concern since it results from Arabic culture.
This is not a call to literally go back to historical practices. It is more like how Renaissance writers placed emphasis on resurrecting the values of classical antiquity.
Other theories place other things at their substructure. Marxism focuses on economies. However, the view that government is an outgrowth of society (including cultural, religious, and moral views) is echoed by Edmund Burke (the theorist behind conservatism).
Pan-Nationalism
al-Arsuzi definitely sees Ba'athism as pan-national movement. It is intended to be adopted by all countries in the Arabic world.
Although there is some similarity to the Marxist schools, which have a concept of "exporting the revolution", Ba'athism is only interested in the Arabic world.
Political Institutions and Methods
Ba'athism, as articulated by al-Arsuzi, does not mention any particular kinds of institutions. He doesn't describe what kind of government should exist or how its business should be conducted. He doesn't advocate for certain kinds of political strategies or methods to resurrect his desired political order.
Most kinds of political thought do. For example, Juche calls for a strong government which unites the various aspects of Korean society in order to ensure their independence from non-Koreans. Leninism advocates for workers to create a vanguard party to dispose of their enemies and create a dictatorship. Marxism suspected that the state would wither away and die.
