hi martin
i have ping zings and i know by the feel if i hit it on the sweet spot or more out towards the toe. to say you get no feedback is rubish. you do get more feedback with blades but you make out that with cavity back your hitting with no feel at all and cant tell when you hit it sweet.
i know when i hit it sweet as i dont feel the ball on the club face at all. i also know if i hit it more out the toe i lose about 5 to 7 yards with my 5 iron.
i dont think cavity back or blades are best in all things, it's what suits your game and what helps you improve and both work for diffrent people, you do get cavity back blades too. ping i3+ that dimarco uses and calcavaca uses too, by your way of thinking there lesser players using pings than using real blades. golf clubs are a tool and you use what you find works and feels good to you, its called choice, i like the feel of my zings and the way the look, i dont like the look of blades as much including the new pings. i know lee westwood thinks the same and wont change.
going by what you say people should not use hybrids as there easy to play compaired with say a 3 iron blade and you wont get the same feedback. i'm sure there are a lot of cavity back players on here that get tons of feedback with there shots. maybe not as much as with blades but that dont make them a second class golfer to blade players as you seem to be making out.
most pros play the clubs they get paid to play with and not always the ones of there choice. but if pings were so bad for there game no pro would use them as they would never win on tour and thats just not the case at all.
bill