Is random brush pattern offset/rotate possible in krita? Is there a future plan for this? I think this indeed is a very important feature to mimic the natural media.

Brush tip/pattern rotation can be controlled by adjustments in the brush preset settings which you can edit fairly easily. The 'Edit brush settings' icon is on the toolbar and uses the same icon as your currently selected brush.

The usual use of rotation is to have it vary with Drawing Angle but it can be made to vary according to different control inputs (e.g. Pressure, Speed, Time) and you can also give it random variation on a per dab (Fuzzy Dab) or per stroke (Fuzzy Stroke) basis.

There is (as far as I can tell) no way of applying offset to the brush tip/pattern but you could get that effect by using a .gih (animated, GIMP image hose) brush with the same brush image repeated with a random offset on each layer. You could take a copy of any brush image and edit it to make it a .gih brush with random offset in that way.