The trailing edge shape of the RV-14 elevators was selected for a number of reasons but none of them were to do with
"dampening some sort of flutter, air flow efficiency, maybe easier to fabricate than a folded edge, something unique to get folks talking or scratching their heads, . . ."
The RV-14 has been flight tested to a high level of detail.
This includes test flights by a lot of different pilots doing a lot of different types of tests. Some of which even included use of stick force measurements acquired using pound scales and a custom control stick with strain gauges.
During the course of this testing, a couple of subtle differences in handing qualities when compared to some of the other RV's, were noted.
As a result, design effort was invested to make adjustment to these by making a change to the trailing edge shape of the elevators.
This removed a very minor dead band in the elevator control circuit (which by the way, only a very few test pilots who flew the airplane with the original elevators ever made any mention about), and it improved the stick force per G gradient.
There is no down side to the shape (no measured speed difference) other than speculation that it was to resolve a strange "problem".
We look at it more as putting out the effort to make the airplane fly and handle as well as possible.
BTW, an added benefit in designing the RV-14 to this level of detail, is another design change that was made to the control system. The one system link that has always been a challenge to build free of play in side by side RV's is the roll hinge point on the control stick. The bronze bushing. Even if the best fit possible was attained between the bushing and the reamed hole in the stick weldment, there is always some level of slop.
The RV-14 is using sealed bearings for this pivot point on the control column.
The elevator control is silky smooth with no discernible play.