I would define a recession is when the economy has gotten overheated and after a period of clearing inventories and cost cutting things carry on pretty much as they were.
A depression is when the old economic model doesn't work anymore and mal investment and non profitable industries have to be wiped away before resources are reallocated to more productive new industries and initiatives.
I would say the world is closer to the second definition than the first although Australia has fortunately been insulated against the majority of the pain felt around the world due to China's demand for our resources, whether this fortune is temporary or permanent is the big question !
Interesting way of looking at it, and i think you are presenting some good views. However i would 'opinionate' that a depression is more extreme version of yours.
To highlight a practicle example look at Victoria during the early 1990's. We were in a severe economic recession. But it wasnt a depression.
Now compare Victoria in the 1990's to whats happening in the US.
I think it makes for an interesting comparison (and yes i know we are not matching apples with apples, the US is still a super power, Victoria? ha whats that)
Trust me guys if there is a depression, you will know without a doubt. I wouldnt be surprised to see this forum cease to exist for a while.