I do not think that most people understand the difference between the types of FMA Systems that exist. When you brake it down, it goes like this:
Multi-Systems made up from multiple systems and methods of fighting (Example: Doce Pares, Modern Arnis, FCS, San Miguel, PTK )
Province Systems example: Balintawak, Cinco Terros, Tres Terros
Barrio-Barongay Systems- Typically limited to three or four weapon/fighting mediums like stick, knife and empty hands, example- Arnis Balite, Pangamut, Tapido, Tondo Kali
Family Systems- example-Cabales Serrada, Pambuan, Sayok Kali, Tres Manos Bias
Mixed system- example: Kempo Kali, Eskrido
Some of these system are complicated with many different thing to learn like single stick, double stick, pocket stick, dagger, Empty hands-boxing, wrestling, staff, projectile weapons and more.
Some are limited to single stick, knife or bolo and empty hands. Some are as simple as long stick short stick.
Some family systems are very complicated other are not so complicated as it is with provice systems as well, it really gets down to what is the person looking for and what would they like to learn.
I like think it is like making adobo, it is all in the flavor you like and how much work you want to put into it how complicated you like to make it. Just my thoughts!