Ok I've just recently been lving nin through Potd, just hit lv 50 nin today actually. I still need to sit down with the dummy at my FC and learn the mudra combinations fully but with the simple ones I do know (the lv 30 and 35 ones) and had gotten used to I've been quite enjoying doing the combinations, yea on occasion I have failed at them but oh well just means I need some more practice.

From what I've noted with nin if you take away the ninjutsu all you're left with is a thief class. Sorry I had noticed nin does share multiple skills/traits with thf from ff XI or even change it to where you hit one button to do the desired mudra would just add more buttons to your hotbar and would also take the fun out of doing the combos.