From the looks of the screenshots on the official site you have ground combat/interaction too ...
From some of the write-ups it seems to be something like Morrowind wrt non-linearity (ie: Go where you wish and do pretty much what you wish when you get there) but I have to wonder exactly how 'big' the thing is?
ie: Its supposed to have 48 systems (presumably with one or more planets in each?) but just what proportion of these planets can you actually explore?
Unless its an absolute monster of an install I just don't see how any of them can be that 'big'.