Contrary to what may appear as true at face value, the Lebanese sectarian system is a threat to the existance of the very minorities it aims to "protect". In fact, it is a threat that grows by the day and that must be dealt with as quickly as possible. Otherwise the consequences may be catastrophic to the "spirit" of Lebanon as a country of minorities.
Rough estimates of the sectarian makeup reported in some sources put Christians at about 35 to 40% of the population (see for example wikipedia's page on the demographics of Lebanon)with the Maronites being the biggest Christian sect followed by Greek Orthodox, among other sects like Catholic, Armenian Othodox and Armenian Catholic, and smaller groups like Syriac, Coptic... Similarly the Muslim sects forming a combined 60-65% of the population are divided mainly among Sunni, Shia, Druze, and Alawite. Among the Muslim sects, the Sunnis and Shias form the bulk of the population mass, with roughly equal numbers, possibly with the Shias having a few percent more... The Druze constitute a minority and the Alawites number even less...
It quickly becomes obvious from just looking at the range of sects and numbers in the preceding paragraph that the demographics in Lebanon are rather skewed to the Muslim side, namely towards the Shias and Sunnis. This observation becomes more more relevant when we note that in 1932 Christians constituted over 50% of the population (amazingly on the website of the Lebanese embassy to the US) and have been decreasing in proportion since then. The reasons for the demographic shift are many, but the main point is that it is happening and thus we must deal with it as a fact on the ground.
On the other hand, representation in Lebanon - including in parliament, in government and in particular with the posts of prime minister and president - is governed by a strict sectarian quota whereby the President has to be Maronite, Prime Minister has to be Sunni, the Speaker of the House (Parliament) has to be Shia. Moreover, parliament is also devided among the sects with Christians and Muslims getting 64 seats each for a total of 128. Even more specifically, Maronites get 34 seats, Sunnis get 27, Shias 27, Greek Orthodox 14, Catholics 8, Druze 8, Armenian Orthodox 5, Other Christian 3, and Alawite 2. Add to that, the sects vie for high level public sector jobs following a similar specific sectarian subdivision.
The reason that such a system is a danger to the minorities that it over-represents is exactly that. The mere fact that some sects are over-represented automatically implies that others are under-represented. A quick look at the numbers would immediately reveal that the under-represented sects are the Shias and the Sunnis, who have a combined 54/128= 42% of parliament while possibly constituting close to 60% of the population. Similarly, I suspect that Sunnis and Shias are under-represented in public sector positions and diplomatic positions if the sectarian guidelines are followed (eventhough the Maronite Patriarch was recently implicitly complaining that the opposite is true).
That said, it is also important to note the above observations in the context of the geo-political situation and changing social fabric of the sorrounding Middle East. More specifically, many Shias, disenfranchised with the system, have turned to the fundamentalist and militant Hezbollah which is mainly funded and sponsored by the regime in Iran. The Sunnis on the other hand were previously led largely by the late Rafic Hariri whos absence arguably makes the Sunni community much more permeable to influence from radical and fundamentalist groups.
So the main things to note here are that the Sunnis and Shias (most probably) together constitute a majority in Lebanon. Moreover, under the current system they are under-represented in parliament as well as (probably) public sector jobs. Add to that, the majority of the Shias currently follow a radical group sponsored by a regime like Iran, while the Sunnis with the death of Hariri are more open to influence from religious populist groups.
Reading the situation as it is laid out above, it becomes clear that the sectarian system as it currently stand is not sustainable. Under the weight of population growth, and hence increasing poverty and under-representation, the large Muslim sects could gradually become less and less tolerant of the status quo. Which is where things could get dangerous. If the other sects refuse to acknowledge those facts and decide to selfishly stick to the system as it currently is, the wrath of larger sects whos religious identity is open to growth might be hard to handle. Mix that with the tensions currently seen between the Sunnis and Shias and you are left with a complicated and volatile situation that nobody could predict or manipulate effectively as the last Lebanese civil war amply proves.
Which leads to a very simple conclusion. To protect the existance of minorities in Lebanon, and thus the religious diversity it exhibits, these minorities have to make concessions. In fact, one could argue that these "concessions" do not necessarily have to be painful ones. To the contrary, they could take a form whereby short-term losses would be more than compensated for by a system that leaves Lebanese sects satisfied in the long run. I argue that such a system necessarily has to be non-sectarian, preferably outrightly secular. Otherwise, over the years as the demographics of Lebanon continuously change and the sects compete for control and hegemony, breaking point after breaking point will be encountered and turmoil will be the order of the day for a long time to come. It is time that we take responsibility and develop a system that ensures a stable future guaranteeing the rights of all religious groups, while simultaneously being sufficiently secular to automatically compensate for demographic changes.