Your examples here don't really apply.
Ishida has been slightly-important, more important than the other 'friends'; but you can be 100% sure that he is going to be important as hell in this arc.
It was established from the beginning that Ichigo rolls solo because he is simply a class above them when it comes to his abilities and powers. He has friends, and he cherishes them, but they are just don't have a place in Ichigo's world. He advanced at such a pace that it was only natural for them to fall behind. Whether or not you agree with the quality of the treatment here is one thing.
The only real thing that used to stump me was Orihime's powers. But then I realized that they aren't underutilized either. A lot of the characters in Bleach are brimming with pride to a fault. Most of them would never use Orihime's ability to reverse events in a closed space for the sake of their ineptitude in battle. Any other time, she healed everyone else. And if it weren't for healing, it was because someone intelligent (Aizen) was trying to use it for his own good, or at least, fronting like he was. I feel that Kisuke would find a way to use it, but he won't, because to use Orihime would be to lose Ichigo's trust, and that is counterproductive for him.
Retcon: You changed your post completely with that retcon; nullifying my post for the most part. BooThisMan.gif