Guran, I fully take on board what you are saying. All I am saying is that in more than 30 years of playing I've never felt that the hand straps on my instruments were a problem, when properly adjusted. None of the points you list as "defects" are problems to me.

I agree that stability can be an issue, but I don't rely on the straps alone for this - I usually support one end of the instrument. I'm not convinced that what you are proposing is the answer, because if the hand is to be allowed sufficient freedom of movement then stability is going to be compromised.

I would be curious to try out an instrument with the modifications you're suggesting. However, as I said in my previous post, it seems to be a solution to problems I don't find myself facing.

As for the air button, it is only dysfunctional in terms of the end joint of the thumb. The thumb is perfectly capable of sideways movement from the first joint. Since I'm using the thumb to exert pressure to control tension in the strap, it's more natural for me to use sideways pressure on the air button rather than a downward lever, although I can see that with thumbstraps you would have to use a lever.

(PS Henrik's instrument, when I last saw it and as illustrated on his website, has both thumb and handstraps - on an English. As you say, this is in part because he plays Irish music and wants to make more use of the bellows)