Its an interesting idea. Fits a rather specialized niche, but it would be kinda neat. Essentually just make league races part of the game, rather than making the game do the league races. Although useless for pickup games, and leagues can already do much of this (and a little more) with a little effort...
I think the major benifits would be the tyres (being limited to a number other than unlimited sets, either over a season or for a particular round. Especially once the tyre physics are completed), and things of that nature that are really just too much of a pain to moniter as currently is.
However, if I may make a minor suggestive improvement...
Remove the stock setup option. As far as I know, no racing series forces its racing teams to use cars with specific settings. Its just way to hard to enforce in real life, and I see no real bonus for using it in LFS.
For the no tyre change from qual to race start... What would the drop in tyre tempature be like? I know if I let my car sit on R2s for a little too long, such as say, the cars are lining up in their appropraite spots to race and just sitting there, they will turn BLACK. Seriously, its kinda funny to watch me drive on 25 degree celcius tyres, but my point is: Would there be a scripted drop in tempatures, so only wear is carried over?
Thirdly, for endurance type races... An option to allow a team to net some points for completing a certain percentage of race may be interesting. Such as, say, in a 24 hour race, if the team completes 85% of it and has to DNF because of mechanical failure, they still have a chance to net some points for simply completing enough of it.
Anywho, enough of my talking...