For me, Invisible War was bounds better than Deus Ex. Not that the latter was a bad game by any means, but IW improves on it in almost every aspect. More lively maps, more detailed factions, more interesting side-quests, more engaging plot, more options in gameplay, more balanced mechanics. People are welcome to their own opinions, but I think most of the negatives are positives. The "simplified" controls are more intuitive. The smaller maps are more intimate, better-designed and take after other immersive sims. Load times were almost a non-issue. The inventory requires intelligent decisions without making gameplay a chore. The augmentations are more useful. The stealth gameplay isn't broken anymore. The lack of a skill system improves the flow of gameplay and offers more choices from the start without railroading you into one playstyle half the game based on decisions you make before you understand what you're doing. The graphics - not that big a deal - were better, with more realistic animations and more detailed environments. The shorter length prevents it from dragging on too long. The less-dreary atmosphere hooked me. In the end, Invisible War is a well-made game. It's not a hodgepodge of mechanics. It feels intentional, intelligent, and - yes - accessible. It's a refinement of mechanics, with a tighter focus, a tighter construction. It's easy to see why later Deus Ex games would iterate on what's seen here, because at the end of the day it's still Deus Ex...just better.
