Decrease the distance between sending group address and setting group address

Makes sense.

And for binary values, don't show a dropdown list for Value, just give a button to write '0' and '1'.

Or maybe for each datatype, instead of dropdown list, show same fields you normaly get when right click on group address > write value.

Why not the ON/OFF buttons in the group address panel?
And for 1 and 2 byte values a number field with a 'Send button'.