How exactly would it make the racing more interesting? After a while the fast guys will still be fast, so what will have changed apart from new guys taking longer to get up to speed and accidents being more likely to happen?
You could always just run all the tracks in open config mode, that gets rid of the racing line
iRacing doesn't have a racing line and I and others from LFS who use the racing line do perfectly fine there without one. And what is the racing line anyway, except a big red thing on the tarmac to give you a reference point where to brake? At Okayama, iRacing's newest track, T1 has tyre skid/rubber marks on the track going into the turn, at Road Atlanta's chicane there's white lines on the road, and being real life tracks they generally have more braking markers and better reference points than LFS.