GS2 is actually a pretty damn powerful language if used right. You just have to have the right programming experience. I know that GS1 was great for even it's time and it's still a good beginners engine. The only problem with it was all the workarounds you'd have to use which made it difficult to handle for some.

I'd recommend starting small, like Graal, and then gradually building your way towards a more advanced developer. Don't just think that since you know a little scripting you can do anything, it's a mistake you don't want to make, especially when you realize you're way in over your head.