The Xposed Framework and its associated modules are the best friends of users who know their way around root-level tools, but don't want a full custom ROM (or can't find one for their less-popular devices). One downside is that Xposed is the passion project of a single developer, "rovo89." He (we have it on fairly good authority that it is he, though the dev is very private) works on the framework outside of his day job, and it's often several months before rovo89 has it working to a level that's ready for general users.
On that note, the developer is still very much active and currently trying to get the framework up and running for Android 7.0. According to a post on XDA-Developers, difficulty is arising in some of the changes to the Android Runtime. In layman's terms, some of the changes that Google made to improve the speed of Android and apps in general has made modifying the core ROM with Xposed's modules more difficult. Between increased complexity in Android itself and rovo89's personal life, things are going pretty slow.
That results in various different compilation states and more complexity. Besides that, there were many issues in the past caused by Xposed's need to recompile the whole ROM and all apps: It sometimes caused boot loops when the odex files were too heavily pre-optimized, it blocked quite some storage space to store the recompiled files, and I needed to disable some optimizations like inlining and direct pointer calls. I hope that I can make use of the JIT compiler to avoid that in Nougat.
Since Xposed is provided for free to all, I'm sure no one will begrudge the developer for taking his time to get it running properly. Right now rovo89 is trying several methods to work with the JIT compiler and its ahead-of-time implementation (including possibly avoiding the entire ROM recompilation of previous versions), but there's no estimated time of arrival for Xposed on Nougat as yet.