I'm also not convinced. there will likely be a part 2 seeing as there is a announcement coming up for tokyo ghoul, and we already know about the second season so it's not that.
Being a Kaneki fan, I was very upset over that ending.
But now I have gotten over it. RIP Kaneki. U_U
Although I would like too have a sequel to get all the unanswered questions answered.
Kaneki could still be alive, believe it! His case (omg the pun intended ) might look closed but maybe it's not.
Not that I really care about him BUT I think he is the only one who can continue as a protagonist should the series continue (which is what most people think).