I have a GSA and a 530 EXC....and I can tell you that I love them both for the jobs they are made for. The GSA is a very capable bike offroad - if you are willing to stay on the gas and keep it moving. Slow down and you're done. In the mud/sand it's a beast, but with decent tires it will go better than you'd think. There are two huge problems though:
First, if you are really "adventure riding" then having a 600lb behemoth just does not work. They fall like a brick and are a bitch to pick up on any sort of incline / soft ground. Anytime you want to do a water crossing or get into a spot where you need to cross over stuff, you really need to watch the weight. For instance, using local bridges or little boats - it's very easy to find out you just can't use local transport and then need to go far out of your way to get to the other side. It really doesn't help that people tend to overpack like manhattan women at a shoe sale on the big bikes either.
Secondly, there is the issue of crashing. Although to be fair, I will say the big KTM's are much better at taking the hits without so much damage compared to the BMW's. crashing on the big bikes can cause a lot of damage which costs a bundle to fix, and take more time to do the work on, generally because there's just more stuff that needs to come apart to do the work.
The 530 however, is just plain fantastic for serious trail work - that you need to ride too. I say that because ideally it would be great to ride a 200 on trails where the lighter weight and better maneuverability is just that much better. But I've done 200 mile days on it (mixture road / dirt) and its just a gem. The only thing I would do is get FI so I am not fiddling with a carb, but even then, that brings its own issues - so again, for true "adventure riding" I personally think a carb is an advantage. Also, it helps with the overpacking issues, you can pick it up yourself, it will out handle any big bike offroad and is very easy to work on.
For me, it's a clear delineation; the GSA is for my long rides/tours that gives me the option for some light offroad to get to out of the way places a true touring bike can't do, and the 530 for true offroading/camping/adventure riding. It's a lot faster on the road than people think too - but the small oil capacity limits the kind of riding where you'd be putting on high mileage highway riding.