the system manager allows some rather unusual input that can result to weird terain, like this: also increasing the height range we can get real mountains!!!, it's playable as well. think this should be fixed as i can easily crash servers.
If you have details about systems which might actually crash server (not client) then you can post it on bugtracker. But I don't see anything bad in allowing user-input data as long as server ignore such broken planets.
the problem is the server accepts most inputs i could play on a planet with hightrange 250 perfectly, there are probably cases that crash the server however planets with a bigger hightrange are quite fun to play on
i've tested some more and you can't crash the server, however you can still generate weird terrain and play on it
In previous versions you were able to play on 3000 meters planet and this affect servers by high memory usage, but I don't see why high height range might be bad.