To avoid takedowns, my school actually likes to practice W.C a couple inches closer in than typical W.C range, and it actually helps to neutralize a lot of that. I know a lot of people have the "if he tries to throw you down, chop him in the back of the neck" mentality, but the problem with that is because of the guy's forward momentum you'll more than likely just end up bouncing off.
I also like to incorporate Northern Shaolin techniques into my WC. An example is that when some dude tries to grab my waist/legs to take me down, I bring whichever leg is forward back and shift into a reverse bow/archer stance and then spring back forward not unlike Tai Chi. It sounds silly but it's worked every time.
Not sure if that would work against the Gracies. Interesting to try it against them.