Hehe! Love your article. I felt free to share my thoughts:
Velocity = Distance / Time
So, to know your pace, you need to keep track of distance and time.
Time, you know. You can see it in the sprints in the past. All you need to do is define something useful that you can use for distance. Many organisations use complexity for that.
It's that simple...
(And that's why using time to estimate a story doesn't make any sense either.)
(And yes, creating big stories doesn't make sense because with those there's no estimating how long it will take to complete it... That's true regardless of the estimation method... We need to throw rocks and rotten fruit at people that make big stories.)