I hadn't noticed the decrease of cops (I'm not entirely sure it's true), but I've been playing without HUD and mini-map for a week now, and it is WAY more fun. Not because it is harder, but you're actually spending time getting to know a neighbourhood, a building, a street, a landmark, instead of focussing on how it looks topdown. Well, that might be personal but I noticed that I'm always looking at the mini-map instead of the actual game. You'll be surprised how much cool stuff you miss that way.
(Also disabled auto-aim, which makes headshot wayyy more satisfying).