Well, despite the graphics, it was a really good game when it has been released.
Also DX didn't got "shortcuts" and such, but "alternative paths" - they often are at the same lenght than the "normal" path, but they are different. Like it was written above already, you could play it as a generic shooter, you could sneak past all enemies, hell, you don't need to fire a gun in most cases. Additionally all that text, newspapers, notes and so on. Also if I remember correct, DX was one of the first games with fully voiced dialogues and it was quite a lot dialogue (especially for a shooter).
I love SystemShock 2 as well, but for me it's totally not like DX1.