Edit - Sorry, meant to post in Legendary Heroes.
I guess at some level color coding units and cities with the strength level makes sense, assuming you're at war with everyone 
Since I'm more of a peacemonger, I don't really care about the potential threat, I care about the strength of monsters and people I'm at war with. The current map scheme has no way that I can see to determine that.
Suggestions (pick some) I like #1, but I could live with #2 and #3 I think.
1) Offer an option to show the civ colors instead of the strength level for units and terrain.
2) Add the civ to the tooltip when mousing over terrain or units.
3) Make it a real threat level and leave the neutrals green.