Since when did I say it was logic? This is all an honest opinion.
But even Project Soul said it themselves that Taki was at that age where she was no longer a ninja. Going by Naruto terms, Taki is either a "Chuunin", a "Jounin", or a "Sannin". Possibly a "Jounin".
But let's be real here. What else would there be for them to do, story-wise, if Project Soul ever were to release SCV based on the previous timeline. It was obvious on SCVI that they weren't doing anything else so they added some random boss character and gave him a backstory. Not to mention many of the characters were doing the exact same tasks they were doing in for nearly 2-3 games (Seong Mina, Setsuka, Mitsurugi, Yun-Seong, Taki) At least Zasalamel's motives changed from 3 to 4.
At least with the new characters, it's like a blank canvas where you can develop them once the series progresses. That's if PS ever makes future installments.