I guess I was spoilt then as I am from back when we had the likes of Peter Kneale at the helm and Geoff Cannell (both sadly no longer with us).
They could talk and talk about the TT for hours which is good for when there are the inevitable hold ups to programme, whenever there's a holdup now it's a case of "oh we'll hand back to Ben in the studio" who then plays the Ting Tings yet again because they have such restricted TT knowledge.
You also get the requests all the time as well again this is only just started creeping in recently because you don't need TT knowledge to read out a naff request.

I think Keith Huewan would be good at the Grandstand, McGuiness (with a bit of training in commentating) at Glen Helen and Whitham maybe at Hairpin.