Its the writers fault, for some reason they wanted him to be a newbie first half of the series. I think they are doing better with him now though.
i agree. he seems to go from being good at the end of a series and becomes a noob for the next. then half way through he makes a leap from noob to slightly more advanced. he needs to stay as good as he was in the last series.
The Doctor: 'People assume that time is a strict progression of cause to effect, but *actually*
from a non-linear, non-subjective viewpoint - it's more like a big ball of wibbly wobbly... time-y wimey... stuff.'
In other words: Time is Complicated.