Sure that's a valid claim(about not needing as much screen time), but 13 episode is never a valid number for any story too big to fit a movie format. However this Isn't any type of story, to makes matters worse, It's a wuxia, you can't fit a wuxia, even the simple ones(which shenmue is more complex then what would be considered simple), into 13 episodes.
For ref, wuxia live action shows are always 45min, so lets go with that, wuxia series average between 30-40 episodes, with the shorter ones only being a few episodes shy of 30(oddly enough the one most like Shenmue, is 50 episodes, but that's a completed series, and stories can differ alittle, so for benefit of the doubt, lets assume the lower, 26-30 episodes).
That's still way more then 13 episodes can pull off. Wuxias can't be sped up(that what I meant by rushed, I wasn't talking about production time).
Lets be real, the whole 13 episode thing, is because the Japanese are very afraid of doing much more then that, due to the insane tax they have on disc type media(6-7 discs sets cost like 300 or so in USD, It's insane. btw, that would only be 26 episodes, yet it would cost consumers a arm and a leg. Also yes, a 50 ep anime would retail at what would=540 bucks USD in Japan).