2 observations here:
1) SFAIK, the top-of-cliff spawns are consequence of where the map designer (usually a volunteer player), put the spawn points, as there is a random positioning factor involved. Actually, the height is usually a big tactical advantage, and so can be considered a feature. In any case, it's not a bug, per se. If you don't want to be up there, it is possible to drive straight down a steep cliff, if you keep the vehicle going straight down, so it doesn't roll. Practice with a non-perk vehicle first. Consider the "driving down a steep cliff" to be a low-rent way of representing mountain roads.
2) Even if it was a bug, which it isn't, the tone of your post is not one which is likely to increase the priority of your request.
MH