It's difficult for me to completely understand the issue you have with your current ride, but I'll offer some comments about my own favorite bike which is supremely comfortable (for me, at least) on week long 100 miles/day "credit card" tours. I should say that at 72, I'm no spring chicken and am not as flexible as I was fifty years ago.

My custom Waterford RS-22 (road-sport geometry) has a 73° head tube angle and 42mm of fork rake, resulting in 59mm of trail. The chainstays are 432mm long, which is a tad longer than most modern frames, but gives me plenty of heel clearance with panniers. The handling is stable but lively, with no surprises.