What about the people that held out for a year or more waiting for a 5d3 and then couldn't afford it, or decided at that price they'd rather invest it other ways like lenses etc.How are those downsides? Those people still could get a 5dII (and $500 cheaper than they would have a year earlier), or, they had a bunch of money saved for great lenses. And they were able to wait because they didn't need the camera. If it affects your business and income, then the decision is easy.
There are many downsides to waiting for the unknown.
I'd say wait for a few reasons. The first is that something new could be announced that you'll want (6D, 70D, etc). The second is because the 7D is gonna be around for a while, so, its not like you are gonna miss out on it by waiting. Third, the best deals on cameras come in the holiday season. Last year, Canon was doing body/lens combos that were HUGE savings, so waiting til November for the 7D might save you a few hundred bucks.
If you look at the price chart from last year, the body price dropped $200+ from Sept to Dec: http://www.canonpricewatch.com/product/02849/Canon-EOS-7D-price.html