It does support classes with strongly typed fields, though, which are the next best thing. It's just a poorly designed API, it's not a reflection of language limitations.

Exactly. Why can't it return a RaycastResult or whatever.

In this sense it's like Lua right? And people don't complain (much) about using Lua in gamedev

If you want "structs" in GDScript, use Resources.

I know it's not the same thing at all but it's as close as you're going to get.