I like that the levels are tweaked as well! I've often thought it would be fun to have a second mode for maps, with different guard placement, so that areas not used in one mode will get used in the other. This will do that! Maybe we'll even get NPCs in the lawyer's office in Sapienza!
I wonder how this will work with contract creation? If the levels weren't tweaked, then you could play the same level on either difficulty. But if disguises are more rare and NPCs are different, contracts could play really differently and might even be impossible in one mode but not the other. I can imagine making a puzzle that would depend on a guard coming to search an area where something fishy happened on camera... it'd only really work in professional mode.
And how about elusive targets? Can we play them on either difficulty?