Typically you have to trade off dutch-roll against spiral instability - getting both good is difficult.
It is typical to select a stable, damped dutch roll and allow slight spiral instability as this is more comfortable and safer than an underdamped dutch roll.
Of course WW1 aircraft were designed before this consensus on desirable characteristics was reached, so modern light aircraft are not in all respects a good analogue. The need to trade one against the other is true though, so you should either see a tendancy to hunt laterally, or a tendancy to spiral dive. If neither occurs then there may be some problem with this portion of the FM.
I know modern aircraft arn't the best comparison, but they still fly under the same set of physics.
For a fighter you would want less stability. Less stability = more maneuverable.
One other thing to consider is that when you let go of the stick in the sim, it goes to a preset held position, instead of following the airflow like it wants too. Right now letting go of the stick is the same as holding some back pressure in a real aircraft.
Supposedly these fighters are tail heavy, but the way the controls work it prevents them from displaying one of the earliest signs of being tail heavy. As the weight is moved rearward the pitch stability is decreased.
It's starting to get tail heavy when you pitch the nose to a certain point, let go of the controls and the nose stays at that pitch attitude. Instead of seeking back to it's desired attitude and attack angle for the airspeed it is trimmed at.
It's getting really tail heavy when you pitch to a certain attitude, let go and the nose continues going that direction. You better be on your toes or you may get a bad case of pilot induced oscillation.
With the controls always centering, ending up with a little up elevator, these tendencies go unnoticed if they are modeled. Surely none were so tail heavy for the second scenario, but the first is likely as it adds more maneuverability.
Remember what was said about the Camel, that it has to be flown at all times. The others aren't mentioned as being so bad, but I bet they were no pussycats.