I've hunted quite a bit with longbows and have tried about all styles.....from straight Hill-style to radical R/D.
The Hill-style was the hardest for me to shoot --------The longbows with real radically reflexed limbs had great speed,but were somewhat finicky for me.IMO it was because the limbs were somewhat noodlely(is that a word) and lacked vertical stability.
My personal favorite was a 66" somewhat mild R/D longbow with a longer than normal riser lenth(22" I believe it was).This gave it nice mass weight and was the best shooting longbow for ME.
Having said all that...........I am much more accurate with a recurve and it's the bow I hunt with.
I think from our understanding of bow stability, can be estabilshed by way of grip repeatability, hence our top "target" longbow has a pistol grip vs the HH style grip that has little in the way of identifiable features, when looked at vertically, the other point that is your point that heavy R/D bows ie Hybrids can have issues with respect to what ive mentioned above.
Some limbs pull the string forward and some push the tip forward, and the ones that push the tip forward are ones that need more thinking to sort the design out.
I fully agree with your observations.
Lets explore this...
would a recurve work with thick/narrow limbs like a HH bow...
NO.
Do hybrids work with thin, Narrow HH style limbs.
NO.
HH style bows do handle them well, id think its the slow arrow speed, and lack of grip repetition that makes the fussy for some. (oh and closing your eyes with expectation of hand shock)
so the more you flick the limb forward the more limb width you need to make the limb stable.
The MAIN aspect is the if the nock is INFRONT of any part of the limb at brace height, the nock it being pushed forward. and this makes the limb unstable. (Heavy R/D bows at brace height has alot of limb length infront of the inflection point on the limb) R/D bows and recurves cant survive with skinny limbs.
Bows with continious D shape at brace height is more stable by default as your pulling the tip forward at all times during the draw cycle.
A example of this, how far can you pull a trailor. vs How far can you push a trailor. one wants to jack knife while the other just keeps plodding along.
Speed can be a killer, if the understanding of this idea is not followed...
We have seen quite a few longbow designs that have a continious "D" shape, that have cross weave technology in them. When in essence there is no need as the limb follows for ever....
Recurves with thier 1.75" limb width is enough to keep a simple recurve profile in check, and thats where our observations of our XP10 concept brightened up our day back in 1999... you can change the paradigm of stabilty vs recurve design... we have been looking at materials, and design ever since.
So with this chase for speed, bow makers loose two main aspects, High preload leading to noodly limbs, and mass reduction of the out parts of the limbs making them skinny, leading to horizontal instability (release issues)
With the advent of modern materials (being sooo dam light) we dont see why the big boys are still making limbs with Earl Hoyts UD glass limb profile. Carbon changes the rules on bow design. We have never seen a better time for bow designers... Im just surprised no one else has seen this yet... Super recurves are the way forward and big tooling expenses follow those that want to play.
For example if every limb progression had a different profile, they would need to re-jig their entire workshop for every model...
I think this is a great time to be a smaller bow maker. If only carbon was easy to handle and incorporate into a bow.