No it is not. Even if part of it to be established and governed by PKK/YPG, they cannot be a threat since from there on they would have something to lose and something stationary for Turkey to target like the state's infrastructure and their regular army. If they want to remain as a threat, they should stick to their guerilla tactics.
Forming a state and using its lands and infrastructure to wage a war against a country like Turkey would be plain retarded and suicide. Not even worth discussing.
Besides, it would be highly dependent on Turkey and cannot survive without Turkey's economical cooperation, hence it cannot survive without Turkey's consent.
However, it might create some cultural and social problems. We'll see...