In .NET there are a lot of premade static readonly instances of classes for common usage. If C# SDL used them instead of creating new instances all the time, it should be possible to gain performance and reduce overhead.
Examples:
new System.Drawing.Point(0, 0) can be written as System.Drawing.Point.Empty
new System.Drawing.Size(0, 0) can be written as System.Drawing.Size.Empty
...
Indirectly related: It would be nice, if C# SDL consequently used String.Empty instead of "". Right now it is a bit mixed which can be irritating.
A lot of the things above is in the taosdl-library and not in SDL.Net. We will look into this when we build our own version of tao, but for now we will not change it.