I use Geany all the time, as a replacement for Pluma, but it is not without issues.
1. As a Latex user, I miss I miss "Forward Search" with Okular, which cannot be set up on Geany due to the fact that Geany doesn't provide a complete set of "Wildcard" parameters for use in command line specifications. GEdit is a bit more flexible in this respect. This has been a topic on the Geany forums, and the author admits that the required feature is "not yet implemented". This is not a problem with Okular itself: Kyle has no problems with Okular and forward search.
2. Geany has become slower and more laggy in its later versions, even on my (very fast) machine. In particular the clipboard bogs things down.
3. Geany's implementation of shortcut keys is somewhat ad hoc and disorganized. One can wrestle the thing into place, but it doesn't approach the big guys, like emacs. (To be fair, what does?) For example the shortcuts for "build", "compile", etc are restricted to a fixed "Build" menu with a somewhat idiosyncratic structure.
4. Maybe "the" central feature of a Linux editor of this type is the quality and flexibility of the virtual terminal. Emacs is the champ here, but a nightmare to set up. Geany beats Pluma but there are issues: Using Geany as a text-based frontend for Python, for example, the VTE sometimes "looses the script" and has to be restarted. Moreover, a crash in the program one is writing will often destroy your session: There needs to be some generic form of recovery. The key feature of Geany's VTE is the ability to send text from the editor into whatever process is running from the command line. This needs a lot more attention, more configurability and a good cleanup.
There are many other issues. Perhaps making a Geany "lite" will be an opportunity to clean up Geany. Hopefully "lite" doesn't mean "less useful as a programmer's editor".