I have been playing this for a while and largely agree with you. However, both the hacking and the cracking took me a few times to figure out, which kinda added to the fun to me. There is actually a clear foolproof way of doing both, but you need audio for the safe, as is clearly mentioned somewhere.
Maps are not always 'solvable' in a stealthy way indeed, which is also clearly explained somewhere. It also adds to the experience in my opinion. Sometimes when the big bucks are hard to reach I just bust in, grab a statue to at least cover my expenses and then bolt.
Fully agree with the off-screen thing as well, it annoys me sometimes, ruining a perfectly do-able house because one burglar escaped already.