There's a generation gap here. The information density in current game UIs is high with status indicators, aiming aids, location markers, objective lists. Players expect the game to be a DM giving them lots hints on how to proceed through the game. At the time Deus Ex was made one of the talking points was realism. Players wanted to experience the game as a simulation. The hand-holding that's expected today was frowned upon as breaking the immersion. The article briefly touches on this debate between realism vs playability with regards to level design.