I play with custom view, only view I ever use. It is a hood/roof cam. However, if I play in cockpit view, it isn't much of a problem, I can be just as fast if I stuck with it. My driving skill really isn't that much different, only I am able to see around me more, which is unrealistic. Having a cockpit only mode is a great idea, and people need to adjust to driving a car at any view really... and primarily cockpit view.
The other choice people make is driver's seat position. Left or right seat position is always a choice for people depending on their usual layouts where they live. However, for fast driving, people use it as an advantage to gain more weight on one side of the car. If this was restricted (one seat position), then I would be quite happy. Because this also leaves me to another point why custom views are unrealistic and used to gain an advantage. If any driver wants to switch their seat position to the left or the right, it won't matter if you use a custom view, their position is not changed.
In all, I can see why people would want to use custom view, but it leaves disadvantages and advantages on the track, and that isn't fun. Personally, I like using my custom view, but I feel it is a bit dissapointing I use such a view, while others use cockpit view and are stuck with a limited visual range. I mean, I have my custom view cranked to its highest vertically so I can see into apexes a lot better, centered in the middle of a car, and able to see the left and right side of my car so I can allow cars to get really close to me. That isn't realistic.
So if you want to go on about how you love your custom view, I can go on about mine and tell everyone how cheap it is because I gain an advantage over other drivers. I'd much rather see a server that restricts your view to cockpit view, and have EVERYONE using the same seating position so we can all race at an equal level with an equal challenge. That is one of the main principles behind this entire suggestion.