This one is interesting, and you definitely don’t need my forgiveness, as you did nothing wrong. 
One of the first things I did was to look for Haiku IDEs. I am using Emacs as an IDE, but I wanted to see what’s natively available and try it. I installed Genio and used it for my first experiments with the Haiku API. The fact it is based on Scintilla was a big plus for me to pick it up, as I was playing with Scintilla-based editors in the past.
What I did so far was just start with a simple API tutorial, then gradually add more features to it using the API documentation as a reference. The only thing that I didn’t need to spend time to learn was the IDE. Genio is easy to use and it did that job quite nicely! It gave me reasonable defaults for a new project, and from those I actually learned a few things I didn’t know, like the Haiku newbie that I am. However, I couldn’t find a way to change a few things, such as confirmation to save unsaved files before building a project, set tabs to spaces (or not). Autocompletion, Go to definition, Go to declaration are there but I couldn’t make them work and they work great.
One of the things you should consider is a way to add more language support. I realize Genio is for Haiku (thus C++) projects, but using a different IDE depending on the programming language is a pain, not to mention some projects are multilingual. This is one of the main reasons I am stuck with Emacs, actually.
Just the plugin framework (or whatever you want to call it) for adding language support should suffice. Some do this with scripting languages like Python, Lua, etc, but I think something simpler should be ok.
It doesn’t need to be anything fancy nor has to support many languages out of the box. This could be users’ job. For example, (modern) Fortran is the language I mainly use (it’s great for number crunching, but I wrote multimedia libraries with it as well, and they work great on Haiku). I wouldn’t expect developers to add Fortran support for me, as I realize it’s not exactly popular nowadays. But I would gladly do it myself, if Genio gave me the means to do so.
I hope it’s obvious the above were written with all due respect to the developers, and only as humble remarks. Every project should focus on developers’ vision, and whatever a random user (like myself) says should come third - not even second.
Last but not least, judging from the “About” window in Genio (which I found refreshingly special), we are una faccia, una razza, if that makes sense. 