Hi Egon,
i thought of a situation which i am not sure is necessary at all, that temporarily switching the render target.
if that happens, a getRenderTarget method can ease the problem of (the engine user) keeping track which texture is the current target.
like this:
b=getRenderTarget();
setRenderTarget(a);
render something;
setRenderTarget(b);
but if the engine doesn't call setRenderTarget, only the app code call it, then the user can use a global variable to keep track of the target texture. then getRenderTarget is unnecessary.
and temporarily switching render target might be a wrong thing to do.