I would like to say, what people would need:
One, extremely big team, who would offer all about racing. Like CTRA did! That was the key for high amount people.
But altough there is many different kind of racing types, there should be something which would add them all!
for example (these are not in any order and only for examples) :
Multiclass Racing Unrestricted (Road cars)
Multiclass Racing Restricted only ( Road cars)
Open Wheel Racing
GTR Racing ( GT2, GT3, XF GTR& UF GTR included)
Any racing leagues running, team racing, championship racing
and so on...
Something like this what I think, but the problem is, project would be extremely huge and difficult. But it would for LFS as VERY BIG solid racing combination, and so then there would be not only drifting and cruising what are usually often seen. (there is still racing in LFS more than 50% tough)
just my 2 cents and my idea is not good at all
EDIT: oh sorry, only GT racing server? well just cut all the other stuff off