The 4 ticks per 5 seconds is also incorrect for draconic. It ticks about once every 2 seconds. Instead of .8 multi, it should be a .5, which makes shiradi much much better. The main benefit to draconic is being able to use single target spells and still get the full effect of your mantle. Meteor swarm avoids this, but your other high level spells don't.
You also probably should be running in ice savant if you are going shiradi imo.
If all you care about is damage, I think shiradi is better. But if you want more than damage, draconic / shadowdancer is almost certainly the way to go.
Why Shadowdancer? I see Evasion, Threat Reduction, Spell cooldown reduction and some spell points. Is there more to it? Dont get me wrong, it does look good, just wondering if I am overlooking something more.