That is an interesting thought; however, it takes a bit more then a shared ethnic identity, culture or claim to a historically defunct nation, to create a unified state. I mean Canada and the US are very culturally similar, but citizens in neither countries want to give up their sovereignty or restructure their political systems for the sake of creating a “unity state.” Brotherly states can exist without needing to share the same passport…
The “reality on the ground” is that Algeria is a socialist, one-party, military dictatorship. Do you really think they could/would want to share power with the Moroccan Crown or the absurdity that was Gaddaffi’s Libya? These current political realities are really what’s important, much more so then a shared history/culture/language/religion/ethnicity.
Take another look at Somalia, they have got to be the most homogeneous country in the world, but they couldn’t unite the country all due to the inability of the warlords to effectively share power.
I could go on pulling examples from Europe too. Germany/Austria, Norway/Sweden/Denmark; religion, language and historical/cultural ties should dictate that these countries be merged. However this ignores the historical political events that separated these countries or the current political power structures that insure they stay apart. For example, Austria isn’t going to jump into a German federation unless it’s annexed again.
Annexation is really that only way to insure a clean unification. Morocco did it with Western Sahara, China did it with Tibet, India did it with Goa, even the US did it with northern Mexico. It works great when you have uneven powers and don’t want to mess about (frankly, it’s pretty clean). “We now control this land. You’re all now citizens.”