Introplate inside blend Space?

I know I can probably use an interp in the event graph but would be nice if a blend space could be told to interpolate on key X on and key X off.

For example I have W set as +1 to move forward and S as -1 to move backwards with 0 being idle on key released. As is in if I press W the blend across the blend space will jump as an absolute from 0 to 1 and does not interpolate betwenn the two values.

Granted the blend speed between 0 and 1 can be increased or decreased but is sill just a blend between the two fixed value.

What would be nice is if the blend space could be told to interpolate with out having to exit the blend space on key off and blend across the blend space on key pressed. Key reason to added nicer direction changes with in the blend space with out resorting to a state machine.