In essence, what I'm pretty much asking for is help on reconstructing my assassin, Corrupted Shadowz.
1. New Build
2. Makeover (New armor)
3. New weapon set (Currently using Zealous Celestial Daggers of Enchanting)
Try a theme. What got me back into playing my sin was a number of things. First, as Bobby said, try playing something else that is slow and ponderous (i.e. anything), and you'll be right back with the sin.
Also, I'm not much of a hardcore PvPer, sure I've done HA and all that, but my guild isn't presently into GvG much, so when I do PvP, I AB mostly, as I find it much more fun and entertaining than RA/TA.
But I've found that staying on one character too long can be a detriment, try playing a Dervish, or Elementalist or something on the side for when you're not playing the sin, I've found I really enjoy the Ritualist class due to its versatility and various play styles.
As for build, try things that people don't expect, my favorite thing in AB is using builds that people don't think are viable, and then imagining the look of surprise and horror on their face as their character turns about face and runs for the hills! You can almost see it when they are desperately trying to cast or attack, and then all of a sudden turn and run, very satisfying. Even more so when you catch up to them and slit their throats.
As for a makeover, my sin originally had 1.5k Canthan, then I upgraded to Vabbian (full) and added the FoW boots and gloves. Almost have enough ecto to get the rest of FoW, only 29 more lol. But I will say that Vabbian chest and legs dyed black, with FoW boots and gloves dyed black, and an ancient mask dyed black is very "ninja-esque" but I've decided of late to go a more colorful route, black is so boring and par for the course.
For weapons, nothing beats Shiro's lol. I know people hate the 13 req, but they're badass anyways, and the only vamp set I use. I also have zealous Dragon Scythes and Ebon Zodiacs, my fourth weapon is alternate, usually for farming (either a regular earth staff or an caster ele sword with an inspiration offhand). But there are a lot of cool skins out there, and since sins are not part of the holy trinity (war, ele, monk) gear is usually cheaper than equivalent ones for other classes.
But, while I disagree with ANet's implementation of the HoM, it does provide an incentive to keep going, so perhaps do more dungeon runs for onyx gemstones and fill out your destroyer case, or title grind for the title display.
In all honesty, I've found that the sin class is one of the most versatile between PvP, PvE, and farming, which is why he's also my title farmer. What can also be fun is group chest running, back in the day when Raisu runs were profitable (oni blades and golden phoenix blades) most of my sin's 3000 deaths came from doing those runs in 8 man groups. The social aspect of this game has been killed somewhat by the prevalence of H/H and certain elite PvE skills, but with a little player injection, its a simple matter to get it back. Cooperative PvE can be more fun than any other mode, especially if its just for poops and giigles!
