I actually tried removing the radar early on with jamming in areas (the interference and static shown when you get hit was reused from it) but I found that both playtesters and I myself relied on it heavily to the point that the difficulty seemed to spike quite a bit. I do like the idea of stealth enemies that don't show up at all on the radar, that's a cool concept that I'll definitely explore at some point.
Looking forward to whatever you make, of course!
Thank you!