Remember, the iMac is a "laptop on a stick" - with the exception of the screen (which can be fairly hit or miss) most of the components are laptop components.

I have one of the good mac pros (4,1), I can whip my AMD out and replace it with an Nvidia card, if I was willing to spend the money - however, for the price of a 970, I can drop another 48 Gb in my box which would be more useful than a better video card than what I am currently running.

To the OP, get the latest WINE and most (if not all) of those add-ons will run just fine. The only one that I know of that is a bit balky is Xdresser - for that I have a copy of Parallels.