Apart from the GUI, I just feel like the settings aren't in the right places. Pascal Gladiator also appears to be a bit unstructured.

I don't buy it that the GUI is easily replacable. Maybe restyling the widgets, yes, but not changing the general approach. An IDE is defined by its GUI, and how it allows you to interact with the build system. It is only minor now because almost no settings are exposed, and general functionality is very limited. And from my, admittedly very short, test run, I doubt the interface scales well.