All of Ichigo's friends have gained new powers, except Orihime. She has however learned to use them faster and with better effect. What I would like to see is her ability to erase something from exitance. She could even for instance "heal" an arrancar's mask, turning them back into a normal hollow/menos. What are the potential of each of her ability's:
Santen Kesshun- Is a defensive ability that rejects an event from happening, like being hit by a cero. It, in effect can prevent any event from happening. It should be able to stop anything her will is strong enough to stop, no matter how powerful. Becuase she rejected it as an event, the power of the attack shouldn't matter (although it always breaks in the manga). I can't think of anything else this could do, but there might be other possibilities considering it can stop fate from happening.
Sōten Kisshun- This technique undo's an event that has already happened. Such as "healing" an injury by undoing an attack. It could however go even further and cancel something out of existence, by rejecting the fate of it ever being created. Thus she could erase something’s existence. This has to be her best ability.
Koten Zanshun- This technique is her worst because she has to be willing to kill, which she never is. At best her will to protect brings out it's potential. The attack itself even defies her supposed ability. It creates a field and rejects either side, thus cutting. Is it rejecting that the pieces of what it is cutting are connected?
Bottom line this is all to the realm of speculation, and the dreaded fanfiction. Even so a powered up, and probably under someone else's control Orihime, would be very dangerous. As some other user mentioned, that would be a good movie.