I actually didn't mind the highlighted objects, I know it makes it all a bit Fisher Price but I think it just reduces the amount of time spent aimlessly searching around. Kinda like holding down the alt key in some RPG games to highlight loot. The purists may not like it but for me the real beauty of games like Deus Ex isn't lost, you still have all the plot, characterisations, different approaches, choices to make etc.
I actually think UI enhancements such as this, objective markers etc are things that modern games bring to the table that help to make games more accessible compared to 10+ years ago when you could often find yourself spending 20mins aimlessly wandering around looking for an item, doorway, trigger-point or whatever, adding nothing to the overall game experience with the possible exception of 'exploration'. In my book exploration means taking a look in an area anyway, not treading every board 5 times over while spamming the interact key.