It would be nice if there was a way to disable the fact that fans can push entities around even when blocks are in front of the fan.

This can make it difficult to work around them; it would be nice if you could hide behind a block and not get pushed by the force its producing.

This could be a config option or just disable it altogether as it seems like rather odd behavior.

That would significantly increase server loads. - for example: if you have mob farm with row of 5 fans and about 50 mobs inside, this will cause 5*50 = 250 raytraces per tick (5000 raytraces per second), and single raytrace is already heavy operation.

Ah ok, I wasn't sure of the reasoning behind it.