I would take the deal. Iggy in denver and Josh Smith will be huge, and Gortat is solid. Yes, Cousins will be a beast, but your getting 2 beasts for the price of 1 and 2 guys who you can afford to lose imo.
I agree, Iguodala is in line for a bump in a faster pace Denver offense and Smith is in line for an even bigger bump, larger role in the offense, contract year. Gortat? His numbers should dip a little - no Nash, working in the front court with Scola.
But I'm ambivalent. Assuming this league competes using the standard 9 cats then yes, deal should be a small net gain for you or at worst a wash. Barring injury I don't expect you'd lose this trade, if that helps you decide.
But all three of your incoming players are worse FT shooters than your worst outgoing player (Cousins) so factor in however much that will hurt you. (You already have Dwight Howard. Is FT% a category you can punt? Or is this roto?) Your biggest gain will be in assists. Do you need that?
Also consider that you're dealing two centers for one - not something I ever love to do and the reason I'd lean towards turning the deal down. Try to counter, keep Noah, offer either Smith or Green (by far your two biggest liabilities) or both? Or at least expand the deal to upgrade one or the other.