Let me first explain what I mean by overhaul, I am not saying that Geany has a bad design or something. Geany seemingly now lacks in the way interface is being shown to the end user. Consider editors/ide like sublime text, adobe brackets etc. They don't even have 10% of the features that Geany have but still and end-user is now-a-days more inclined towards using it instead of Geany.
I think few polishes here and there need to be done, may be the icons as well, tab styles, search bars, buttons etc. Basically an interface overhaul.