Actually closetman I had the same fears, after BlizzCon I'm happy to report that you need not fear ;) it is easy to pick out units from the background...

Wall-to-Wall Write on starfeeder's Wall

There needs to be greater graphic distinction between the landscape and the characters. Maybe in the color choices. It seems these two things seem to wash each other out with regards to the overall look of the gameplay. The exception being when the whole screen lights up when something blows up or lightning lights up the sky. Also the look of the armor
needs more color distinction to make each unique article standout ie: boots, gloves, belts,
helms......they all look the same color, kind of like the scenery. .....IMO Otherwise effects look cool.........Hopefully they will take the extra artistic steps necessary to really make D3 exceptional.

Wall-to-Wall Write on closetman's Wall