While you improve the tag loading, would it be possible to also add support for function arguments? If I look correctly, those are not currently processed from ctags, but Geany uses them when they're in tagmanager format.
Ctags do support that, at least for some languages (e.g.: C, Python but probably many others). The only problem is that it is not in the default ctags output format, it must be requested on the command line.