[dogscoff]

not sure, I feel Shotokan spends far too much time copncentrating on kata and not enough on power combinations and defence mitts

It depends where you train. The first place I trained (Coventry Uni - very good club) we had a proper punchbag (one of the full-size, heavy-as-a-person ones hanging from the ceiling), mits, and every Sunday we'd have a 2 hour session devoted to kumite and working on the bags & mitts. Where I am now, the kata and technique is superb but they consider bags & mitts completely unnecessary and turn their noses up slightly at the mere suggestion.

Personally I don't think you can learn to punch and kick properly if you never actually make contact with anything. how do you know you're doing it right otherwise?

I still wouldn't do full- contact though.

As for power combinations... I would argue that they're not really necessary- I've been taught that the whole ethos of Shotokan is that you only need to hit them once.