Part of the reason that this era's Doctor still feels slightly ill defined is that Series 8 was much more interested in Clara than it was in him. This is a perfectly legitimate approach (indeed, most of New-era Who leans heavily toward the companion as the central character). However, as legitimate as is it was in storytelling terms, It's easy to question why they didn't give Peter Capaldi a season to settle into the role before getting distracted with all the 'Will She Stay/Will She Go' shenanigans. With the benefit of hindsight the answer seems blindingly obvious - they genuinely believed that she was going to leave at the end of the season. Therefore, planning on saying goodbye to Jenna at the end of the year, they somewhat maliciously set up the dilemma of Clara having to choose between Danny and the Doctor with the intention that she would lose both of them in the finale. But then Jenna decided to return (and if they knew in advance that she was coming back for the Christmas special - which seems likely - they clearly didn't plan for her to be back in Series 9), so fans got a tearful leaving scene at the end of Death in Heaven... followed by her quick return a few weeks later... followed by a tearful exit/dying scene... interrupted by a last minute save from Santa Claus... followed by her quick return to the TARDIS again. At this point, Clara. Stay, Go, whatever. Just pick one and stop lingering on the doorstep. Ta!