1 and 3 will certainly be added in a future update. 2 sounds good as well, we can have a filter for "bad words" that just blocks the message and shows a warning instead, I think I'll add that in a future update as well (less of a priority though). 4 sounds good as well, I'll just add that in a future update as well.
For 5, there will definitely be a racing system and I have a pretty good idea of how I'll make it, but I haven't started scripting it yet. It's more of a low priority, longer term project. When I get around to it, I'll start a topic where you can add suggestions specifically for races, and an explanation of how the system will work.