Why doesn't SE just make it so ninjutsu doesn't fail when using non-mudra skills? I feel like that would go a long way to fixing the problem.

I do see what SE was trying to accomplish with mudra, and when I get those brief moments of no lag and I can pop off all three signs + ninjutsu before my GCD is finished (or just as it finishes) it feels absolutely amazing. But in reality that's simply not the case 99% of the time and it tends to take a GCD and a half's worth of time to cast.

If they were to remove that failure aspect so we could cast 2-3 signs, do the next part of our rotation, then cast the last sign and/or ninjutsu, I think it would go a very long way to countering dps loss/frustration with the class.

What's more is it would still be (technically) a dps loss this way over the way it's intended. Just not as much as it is now with lag. But since fixing the lag isn't (as far as I know) even possible, this seems like the best solution to me.