The Derby is a different ball game. The Derby winners don't often go for the St Leger these days because they are not bred to go 1m 6f they stick to 1m2f or 1m4f races.
We take the cream like Wayward Lad Pendil Desert Orchid Kauto Star etc and ask them to go that extra mile. Some can but some simply can't....It used to be more popular with the Whitbread being the last big race of the season but look at that race now. It's almost 30 years since the last big name "Dessie" won it no one is interested in running their best horses in it anymore.
Do you realize how few top rated or peoples champions win the Gold Cup we had Mill House, Arkle (3), Captain Christie, Ten Up, Silver Buck, Dawn Run, Burgh Hill Lad, Desert Orchid, Best Mate (3) Kauto Star (2) ..you could add Denman but not in this post because I said so. That's 10 horses in 53 years,
You just need to look at the King George results and it's like a who's who's of top class winners.
If you compare the Leger to the Derby you get the same sort of result.
So for me the Championship distances should be 3m and 1m4f but we're stuck with it now and all we need is another Lord Windemere to pop up and we got another false champion