My Shuriken has a pretty thin neck actually. Probably closer to the JTV 89 from what I can tell. I believe it has more of a Thin "D" vs a Thin "C", which is a little foreign, at least to me. I also have a JTV 69 and the neck on that IMO is really good for people used to Les Paul's and Strat's. It's thicker than a typical Strat "C" neck but has a similar "D" shape (wider shoulders than a C) to the Shuriken. I was going to change the neck out on the 69 for a Warmoth Strat neck but it really is a good neck.
Overall, I personally prefer the JTV 69 neck over the Shuriken. In fact, playing the Shuriken has given me a little bit of pain in the last two weeks I've owned it. It might be from the fact that I play longer because its so damn fun to play though... It might also be that its a baritone and you have to keep the string tension high to reduce plink so bends can be brutal. I own other baritone's including a rare Explorer, an 8 string Mayones Misha Monsoor owned, a PRS, and an ESP and those seem easier to play. Less fatigue.
My all time favorite neck profile is the one on my Strandbergs. Regardless of how many strings (6, 7, 8) it is ergonomically perfect and makes playing for long periods so easy and fatigue free. It's weird for the first thirty seconds and then its like, ahhhhh, brilliant! Thin necks are fun to shred on but they have been proven to contribute to tendonitis. Your hands weren't really made to work that way.
My dream guitar would be the Shuriken with a Strandberg Endurneck profile.
Hope this neck diatribe helps those interested in the Shuriken.