Hello,
Here are my opinions about this:
1) By filtering bad language, you often get into trouble with differences among other languages. Imagine a word "kurva" which is a swearword in Czech. But in Swedish or Indonesian
*), it means "a curve", which is not a bad language at all. I know there are some swear words that (most probably) exist only in one language, but that would probably not be enough. It is almost impossible to have a good and effective swear filter for all languages and nations that play LFS.
2) Well, why not. However, InSim is a good tool for those features, so when the server owner wants the auto restart feature to be there, he downloads that specific InSim application and enables it. But as I say, it wouldn't be a bad thing to have it as a server-side option, it would make things a bit easier for hosts without having to download a whole InSim app just for this feature.
3) I'm afraid there is such host option now, I think it's /carsguest=X, where X is the maximum number of cars (real + AI) which can be on track at the same time from one guest.
4) I'm quite for this suggestion. Now LFSWorld stores all PB's, no matter if they are "valid" or not. It is, however, difficult to detect cheating, because of the way how most cheats work. The whole structure of maintaining car physics data would probably have to be completely rebuild to somehow measure if a car is using original values of power, weight etc. Only my guess though.