Yeah, I have to agree, as much as I want to love GIMP, it's really difficult to do very basic things.

I wish they would work on a way to drag a layer and have it snap to either the X / Y center of the screen or the nearest object, along with seeing a visual indicator (such as a temporary ruler). So many other editors do this seamlessly and it's something you need to do so often when editing many different types of images.

Gimp is actually addressing the problem by developping smart objects. According to the article, thanks to the smart objects you will be able to do your vector-drawing operations (including circle, polygon drawings etc) using Inkscape, and the changes will be automatically reflected in the linked layers in Gimp.

I'm sure there are some people who think "when I want to draw a circle in gimp, I start by installing Inkscape", but I'm surely not one of them.

“If you wish to make an apple pie from scratch, you must first invent the universe.”

If you think of {Gimp, Inkscape} as a toolset, your problem is gone. Especially if when you clic "edit" on your linked shape Inkscape opens automatically: then the frontier between the two is as thin as the frontier between Grep and Sed when you use them together through Bash.

Drawing geometric shapes is inherently vectorial. Not Gimp's purpose.