That's because Deus Ex IW sucked as a RPG. Don't expect TSL to have such a crappy and linear plot development. And yes, you could get both endings in K1 in just one go, but that didn't allow for full exploration of plot and/or gameplay options.
<{POST_SNAPBACK}>
Sorry, slightly offtopic, but Deus Ex was not an RPG, it was an RPG/FPS hybrid. Furthermore, it didn't have a crappy plot development. Perhaps it was linear, but it was one of the best storie I have ever seen in a PC game!
sorry, but I had to step up for DE