C4L: Guadzilla and I are clearly talking about effective top tube length. Which in fact accounts for the seat tube angle, although they make an assumption about seatpost type and extension.

Weight distribution is true, but it doesn't vary much and isn't that significant on a road bike. (Unless a MTB especially when climbing.) Weight distribution is heavily driven by body posture and chainstay length. Same person should be fit the same way on different road bikes, minimizing these contributions.

TL;DR
I still disagree. Reach and stack are not easy to use, but they're what matters for it. Handling is huge, no doubt, but it is something different than fit.