"Civil war trends" sounds more like a political science topic to me. At present, most historians tend to be more interested in addressing particular events or developments rather than generalizing processes. But since, generally speaking, civil wars are a type of phenomenon that interest people across disciplines, inside and out of academia, yes, historians tend to be interested in them, too.

I'm not sure how many "less studied" civil wars are out there. Wikipedia offers a lengthy list of civil wars. Since Wikipedia doesn't allow original research, these all have some degree of scholarly publications already out there. Let's track down one minor example together. To make a fairly random choice, here's the wikipedia page for the Jementah Civil War, a two-month uprising in a small town in Malaysia in 1879. Wikipedia says the government dispatched a force of about 400 soldiers to put the uprising down. The references section points to a single book as well as a website that doesn't list any further sources. So we've got a small civil war with little apparent research. What more can we tell about its research potential?

When you look the one cited book up in a library catalog, such as Worldcat, most catalogs will record that the book deals with two subjects—Segamat (the district where the uprising occurred) and the History of Segamat. Clicking on either of those links will give a short list of works with deal with the locality and likely have at least some information about the uprising. Checking some other online research databases turns up no hits for "Jementah Civil War" on academia.edu or researchgate.net. If you go to ProQuest and search for dissertations including the phrase (this link might take you directly there, or else close enough to do the search), it turns up three, dating from 1962, 1978, and 1995. Only the oldest of these seems to really be on topic. JSTOR also turns up a few possible connections, the most likely one being an article about Chinese people living in Malaysia.

All in all, this seems to be a pretty obscure civil war. There's a few places to find initial traction for research, but it seems like scholars don't see this as being a significant event in itself. That poses a few challenges right off. First, you'd be hard pressed to find primary sources, and you'd likely be working between Malaysian and British archives, dealing in English, Malay, and perhaps more local languages as well. Second, you'd need to broaden your topic to make an argument for why historians should pay attention to this thing. Based on what little work exists around this topic, the most obvious options are a broader history of the region, a look at how this fit into patterns of 19th-century globalization and colonialism, or Islam and revolution, or perhaps a new topic that emerges out of the research itself. That is, a dissertation or book on the Jementah Civil War probably won't find any readers unless it makes an argument that it helps us understand something that people are already reading and arguing about.

In sum, there's generally at least some baseline research out there for most civil war events. In cases where there isn't much already, you've got two main problems. First, finding and reading primary sources that touch on the topic, which might involve learning new languages or obsolete dialects. Second, finding ways in which this thing that nobody currently cares about intersects with things that they already care about. But that's not to discourage you—far from it! Some of the most exciting work historians do involves digging into little-known archives and getting peers and the public excited about things that might otherwise be forgotten.