[Robin Palmer]

On the matter of the best edge for a blade against plate I would draw your attention to the Italian delibera ?( I am not sure of spelling sorry) Who recommends that a barsted or sword of war be given a blunt edge only the front six or eight inches being sharpened to a fine edge.
As has been stated hitting plate even mail with a razor sharp blade will simple fold the edge and do no damage to the blade. Leaving it blunt has two benefits first a chisel edge will not fold but tend to cut into and split the plate it also has benefit in fighting.
Both barsted and sword of war are styles involve sword on sword contact given the power involved sharp edges would see the blades chopping into each other destroying both edges in short order. Chisel edges would take the impact with limited damage to either blade without effecting their ability to deliver telling blows. It also allows the use of half sword style gripping blade to shorten length allowing powerful stabbing moves and guards. The two big flam bards I have seen both had what appeared to be chisel edges they certainly were not sharp unless they had had the edges ground off for some reason.
One further point on swords against plate there are several harness in the Wallis collection which have faint fine lines on various parts of the plate these were left by sword strikes. I do re-enactment and good modern reproduction plate made of 16 gauge sheet will take a blow from a standard single hand broad sword without damage. To dent or split 15th century plate you needed to move up to a barsted or a sword of way two handed and plenty of enthusiasm or switch to pole axe or battle axe. Weapons made to deal with the plate as such the normal rules of sharpness do not apply they would have been given edges ideal for their purpose. The styles lasted well into the mid 1500 by which time armour usage had begun to decline I suspect many may have had edges reground to suit the new targets. I believe that the sharpness of swords has changed almost as much as styles the key factor is the target soft and razor edges are all the rage plate and chisel is the way to go.
Flam bard and scalloped blades were minor deviations on a long road the fact is that none lasted the straight forward plain edge won out in the end because it did the job with the least amount of messing about. There is a saying which I firmly believe in KISS Keep It Stupid Simple if you have a tool which works don't mess with it I think it sums up the flam bard blade when compared with a conventional blade of the same type. They are simply examples of people trying to reinvent the wheel mostly in the hope of relieving some sucker of his cash.