From my experiments I have found that I can adjust the coaxial heli to do just about anything. Note that 'anything' is singular, no plural. You can adjust it for very stable hover. You can adjust it for a decent hover and more manuverabiity. And you can adjust it so it is quite energetic and can hardly be controlled in hover. You can't have it all, but like a grab bag, you can have all of whatever is in the bag.
You want to have a more energetic heli, use a lighter / shorter flybar. IF you take too much weight out the the flybar (or move the weights too close to the center) you will find the heli to be really hard to fly in a small space and also hard to recover from a fast dash across the yard. The opposite of "stable" for a good hover is "unstable" for dynamic flight.

Something that I have noticed is that any vibration makes the flybar less stable. And with that, the heli is more cooperative when I want to fly (not hover). So that does seem to be in line with the thought that the better the hover the worse the flight characteristics - certainly the more pronounced the pendulum effect that you noted in your post.

There are other things that can be done to make the heli more flyable, but the flybar is the cheapest place to start and will teach you more about the dynamics of the coaxial helicopter than any other change you can make. When you get close to what you want, some of the other mods will help you along. Light weight and power are good mates. A heavy heli with a heavy flybar is stable. The flight characteristics you want are in the balance between flybar weight and heli weight.

there ya go - now go play. And stay outa the Christmas tree.

Soloboss