There is an old statement that applies here...and that statement is, "rob Peter to pay Paul." There is a factor of trade offs, for there is no free lunch in all aspects of performance. To excell in one area, you often have to give up something in another area. The goal of a bowyer is to find the perfect "balance" of desired traits for the given task at hand. What is the task? Unauthordox shooting in hunting situations? Tree stand applications? Shooting rabits? Or...is it shooting stationary targets from a static position?
Howard Hill was no fool, but niether are olympic archers. We have to first ask...WHAT TYPE OF SHOOTING you are going to do?
There are several types of stability. Stability comes in terms of forgiveness. There is torsional (or lateral...side to side) stability and there is also "beam strength" (vertical) stability. A longbow is technically more resistent to both than is a recurve. But, at what cost? In GENERAL the "traditional" longbow while more RESISTENT (forgiving/stable) to a shooter's errors is in my opinion also more likely to CAUSE an archer to develop shooting errors. For every action there is an equal an opposite reaction. Generally speaking, a longbow will have more handshock than will a recurve. Of course there ARE EXCEPTIONS to this depending upon the design of the longbow or recurve at hand...as some longbows have practically none, while some recurves thump like a mule...but those sitations are more exception than the rule. Generally, recurves are gentler in the hand than are longbows. For this reason, if an archer shoots a longbow for a long time...a heavy thumper...then they are more likely to develop "reactions" to the thump...and it is my opinion that few longbow archers learn to master that reaction. Howard Hill, Wilhelm brothers, and a few others certainly acheived that task for the distances they shot.
For many however, learning to maintain a proper follow through becomes more difficult as the bow's thump becomes more and more pronounced. This is why we learn to prefer bows that don't have such thump upon release.
For these reasons, it is my opinion that a recurve shooter is less likely to develop "action/reaction" issues, but if they do...their equipment is more likely to reveal poor arrow flight when it does happen. Again...this is of course only a GENERAL STATEMENT and would vary depending upon the quality of the specific bows and/or archer.
Again, the bowyer's goal becomes balancing...obtaining the optimum of the desired traits while also maintaining the minimum of the undesired traits.
Now, we have a lot more information about these trade offs on our site for those that are interested in such readings or videos. I don't wish to "come off as a salesman" so to speak, but instead would like to just offer MY OPINION. Others are free to disagree, but of course I make bows based upon my beliefs. I don't try to change the archery world or anything...but here is a video that illustrates some of my views on stability. The first 3 minutes demonstrate stability, but around 3:30 seconds I begin to explain why this stability matters. Those interested can review it at their will.
http://keepitsimplearchery.com/apps/videos/videos/show/14179600-limb-stability-demo Ultimately, there are some excellent recurves and some excellent longbows. You can find both good and bad examples of either. I think seeking the ideal balance is exactly why many "hybrid" bows have now become extremely desireable...and preferred by so many archers.