I know it isnt the most impotant thing, but it seems like it can be helpful, and especially for people who refrence this and don't know really know when pokemon evolved, but who do want to see which battles a pokemon won in a specific stage, say if prehaps their favorite pokemon is a Charmelelon, and want to check out Ash's Charmeleon's track record.
Maybe something like this ...
Paul's Electabuzz:
Appeared as Elekid in " Two Degrees of Separation " (EP470)
Evolved from Elekid in " Smells Like Team Spirit " (EP520)
Vs Ash's Pikachu - D (EP471)
Vs Roark's Geodude - W (EP483)
Vs Roark's Cranidos - W (EP483)
Vs Ash's Buizel and Conway's Heracross - W (EP520)
Vs Gliscor - UR (EP532)
Vs Team Galactic - UR (EP537)
Vs Drapion - UR (EP549)
Vs Brandon's Regirock - L (EP596)
Vs Ash's Grotle - UR (EP599)
Vs Ash's Monferno - W (EP600)
I'm using Serebii's episode numbering system.
He's already marking down which episodes these battles took place in so putting where the Pokemon evolved can help pinpoint when a Pokemon evolved, I think.