Actually, I think am built a lot like OP - 66.5" in height, 30.75" cycling inseam, 32" or 33" dress shirt sleeve length. I ride a 1973 English road frame, 21" (CTT, since it's English) seat tube, 22" (CTC) top tube, 11 cm Nitto Technomic stem, 73 degree angles, 700C x 28 tires. I weigh a lot more than you do, I think, at 207 lbs. I ride mainly on the ramps. I no longer need the extreme height of the Technomic stem, but I don't have a spare, and changing quill stems is an awful task and what I have is eminently usable. I love riding my bike.

I've got an inch clearance between my sensitive parts and the top tube. That seems to be enough clearance - I think that because I've come down hard in some emergency stops in recent months. I rode a 50 cm Gitane for several years, and I always felt cramped.

Every time I shopped for a bike (last time was late '80s and always for road bikes), salespeople put me on 21"/54CM frames. When I had a mini-fitting last year, the fitter said nothing about my frame's size. I'm within a CM for the Competitive Cyclists 'EDDY' fit.

Frankly, until now I've held back with this post, because I've thought the OP is crazy about his bike fit, and I don't see how saying that would further this discussion.

But actually there could be a number of very reasonable explanations for the differences in our perceptions:

1) One of us made measurement errors
2) OP likes to be more upright and less stretched out than I do
3) One of us is only telling himself that he's comfortable
4) Differences in arm or leg bone lengths
5) OP wants more clearance between him and the top tube than I do
6) etc., etc., etc.

It's interesting that we're so alike in significant measurements and want such different bikes, at least IMO.