I can't relate to the original KI problems that you are alluding too...
but here are my thoughts:
* the brand controller you are using are happs ultimates, i've read that a stiffer spring is sometimes desired for "feel" with these sticks
* Maybe you need to futz with the actuating levers to get easier/more sensitive diagonal action (towards the stick)
* Maybe there's a dips switch setting on the board for "easy combos" that the boards you played on were used to
* Maybe it was a firmware issue and only later KI's played nicer
*shrug* Maybe you need more practice =P
good luck,
rampy