A list of things that would make ten thousand stars viable, not to be taken in conjunction with each other:

1) Make it a passive, always-on enhancement
2) Make it work like many shot, with no cooldown beyond the standard 1 second, but still requiring Ki
3) Increase the attack speed bonus to at least +150%
4) Make returning a much more common trait on good shuriken drops
5) Make the attack speed bonus stack with wind stance and haste
6) Make shuriken attacks generate Ki

I mean, we all know that shurikens are a weak weapon even as far as throwing weapons go. It doesn't help any that finding a returning shuriken other than simple material returning ones from collectible turn-ins is absurdly rare. The skill could certainly use a buff.