Gate Category - It would be nice if there was a text telling me wether it is a small, medium, heavy,(...) position, since the radius of a parking position not always matches its category
I can see the Parking type here but, I must say I'm not entirely sure it's there in the released version, because we'll have another maior update in the next days.
However, knowing the parking type is not that useful, if you want to know if your airplane fits the parking because, as you said yourself, the category might not match the radius, and for GSX, it's the radius that matters, regardless of the category.
But if your goal was to know at a first glance which parking spots are suitable for your airplane, the current yellow circle will do just that, and it's much quicker than having to read the category (which might be misleading).
Parking system - as well an information of which parking system (vdgs, marshaller, none,...) I can expect at that position would be very helpful
Already included in the next update.
And I actually still get the "Parked at wrong parkingposition" when I choose my spot while I am flying.
Is there a fix for this?
Why you think this is something that needs to be "fixed" ? It's how GSX always worked: if you think the airport is wrong, you can easily override this, either by editing the airport profile OR by changing the settings to always ignore the parking radius OR selecting another parking.