I think I've figured out my ideal Mesmer playstyle

I think I've gotten the hang of this whole Mesmer-thing. No saying how well this will do in dungeons or anything, but for now, I've got it!

Defensive Mesmer play, basically, based on shatters and illusion DPS. Start in Scepter + Sword, use Phantasmal Swordsman and start Ether Bolt>Ether Blast>Ether Clone-ing. If something is targeting you, use Illusionary Counter and Illusionary Riposte interchangeably. Use Decoy whenever necessary to generate another illusion. At three illusions, shatter with whatever shatter ability is useful at that moment. If you need more illusions quickly (as in, not enough time to Ether Bolt chain or wait for Decoy/Swordsman to be up), switch to Staff and Phase Retreat and Phantasmal Warlock.
Staff is also the support weapon. More for supporting by giving boons and conditions than shattering, which, while possible in Staff, is harder due to the lack of Ether Bolt.

Reason for using Scepter instead of a main-hand sword is because you can create more illusions quickly with Ether Bolt. And that's with auto-attack. As far as I can tell so far, creating a Clone doesn't override any created Phantasms, but I may be wrong on that. So if you already have a Phantasmal Swordsman up, auto-attacking with Ether Bolt won't make the Swordsman disappear, instead you'll just keep overwriting your Ether-Bolt-Clones over and over until the Swordsman disappears naturally (or you shatter, of course). While with Sword you're only generating illusions through Illusionary Leap, Phantasmal Swordsman, and the occasional Illusionary Riposte. With Scepter I can spam Ether Bolt for quick clones and Illusionary Swordsman, plus I can use Illusionary Counter and Illusionary Riposte on occasion.
It looks to me like Swords are better for a more condition-focused build, which I'm sick of from playing Necromancer.

I'm still working out what I want the traits to look like though. I know I want the most shatter damage I can get.

I might just be crazy though.