If you want to see what's going on with your Flash window, download this util, follow the instructions.
WS Monitor
It shows real time memory usage. Just make sure you're using the same Flash version in both windows if you use a different browser to monitor and play in. I find it works better if you use the same browser.
Also, make sure you don't have other Flash assets running, close other browser windows other than the game client.
From what I've seen, the memory issues people are seeing having is an Adobe issue vs browser/s. It's not specifically a WGT issue with the game. I myself don't get any of the memory problem and I've left the client window open all night with a game running, come back in the morning started playing again with no problems and the monitor is showing maybe around 300mb max usage.
I'm certainly no WGT cheerleader but creating memory leaks in AS is actually pretty tough to do, you have to be pretty brain-dead to cause them, to the extent people are seeing here.
Asset loading issues are a different matter and don't have anything to do with memory leaks, this is a problem I know WGT has in abundance just by the nature of the way the game is developed.
This is what I get on WS after 4 hours or so, game play is smooth with a max client window on a T-61 laptop.