Going Assassin 1 by your progression basically jumps the SA progression by 1 level. Which is nice, though the loss of BAB hurts, IMO. Multiclassing medium BAB classes is rough. I think your build's cool, though. Perhaps do Rogue 4 / Swash 3 / Assassin 1 instead of 2/5/1, though. That way you're still "gaming" the system by bailing on Rogue at an even level, and 4's a nice rogue breakpoint, since you don't lose anymore BAB since level 1, and Uncanny Dodge is pretty important. Also, the Dungeonscape variant for Trap Sense is amazing at Rogue 3. Melee only, but the ability to deal half your SA dice (whether you can add half of Craven is iffy, by strict reading no, it says "dice") against things immune to it is pretty crucial when you consider how many things are immune to it. You should still get greater truedeath crystal and all the other crap to ignore SA immunities when you can, but having that as a backup is still very helpful.
Re: Quickdraw
I'd say to just play as a melee rogue that can throw when needed until MT 1, it would be really foolish to get Quickdraw as a feat and waste the class feature. Or just dip into MT earlier than 9 for a level, go back to the other classes to finish that up, and hop back for 2-5. With up to 4 levels in rogue and up to 3 in swash, you can enter by level 7 easily.
borrowing your format, here's how I'd do the build:
1) Rogue1, SA 1d6, Trapfinding, lvl1 Feat: TWF, Human Feat:
Weapon Focus: Dagger PBS
2) Swash1, Weapon Finesse
3) Rogue2, Evasion, lvl3 Feat:
Point Blank Shot WF: Dagger
4) Rogue3, Penetrating Strike (from Dungeonscape), SA 2d6
5) Rogue4, Uncanny Dodge
6) Swash2, Arcane Stunt, lvl6 feat: Precise Shot
7) MT1, Quickdraw, Thrown Weapon Trick
8) Swash3, Insightful Strike
9) Swordsage1, Quick to Act +1, 6 maneuvers, 1 stance (child of shadow or island of blades), weapon focus [shadow hand] (ask to retrain former feat to Craven), lvl9 feat: Daring Outlaw (bringing SA to 4d6)
10) SS2, 1 maneuver,
Assassin's Stance (bringing SA to 6d6), AC bonus (likely useless)
11-14) Master Thrower 2-5
12) lvl12 feat: Shadow Blade (dex to damage with SH weapons)
15+) Probably want to dip Fighter 1 to help with the TWF tree, then I'd go back to Rogue.
With that build, your sneak attack suddenly balloons like crazy at levels 9 and 10! Especially with Craven if you can retrain.
I do think a small dex boosting race would be better than human, though if you have no flaws to work with, I suppose you need the feat.
EDIT: Weapon Focus requires BAB +1, you have to get point blank shot first.
And if retraining is a no-go, you don't
have to drop your first level in Swordsage at 9, I just like to do that for instant access to level 3 maneuvers. If you went in at 5+, you'd still get 2nd level maneuvers and could take level 2 at 9+ for the stance. Then you'd get Weapon Focus with a bunch of weapons for free and be delayed entry into MT one more level.