I haven't played those games you mentioned, so I'm afraid I won't be much help. I'll toss out one other aspect of my idea I'll share that might inspire your own ideas.
When you consider games such as Runebound, Descent, etc., decks of various cards are used to represent items, treasure, etc. If I had decided to flesh out my own idea, decks of cards would have been a vital tool in fleshing those out. For example, each side would have a deck of location cards. The criminals would secretly allocate their criminals to various locations, and heroes would secretly select a card to indicate locations which they would focus their surveillance. If the criminals can bluff the heroes and be at the bank while the heroes are watching the warehouse, the criminals would be more successful.
So you might have an action deck, equipment deck, etc.
I really hope you will be able to develop something, because I think you could really come up with something really exciting. I'll look forward to seeing what you develop.
