Marakanetz, mid-fi and 3D soundstage don't even go in the same sentence. There are numerous amps that would not compromise the 3D soundstage. It's not the brand, but the quality of the parts, which is why ARC or any other brand will have many different priced models.
If you replaced the parts in a Rotel with the best available, you might get a 3D soundstage; but then it would no longer be a "Rotel".
If you replaced the parts in a Rotel with the best available, you might get a 3D soundstage; but then it would no longer be a "Rotel".