Well, I spoke to Daishi back in the day when SC5 was being developed. He actually talked to me a lot about Talim while not directly saying she was in the game.
I told him once about how I would miss having a character with the wind charmer stance if she were not in the game. He replied to me and told me that with quick step all characters effectively get wind charmer... Eh, not true but meh.
He later asked me why I like to play Talim so much and to see if I could put it into words. I told him that I like her pure spirit and try hard attitude. He told me that Leixia would fit into that category, or maybe Pyrrha. This was before the roster was finalized.
Later when Talking about Talim he asked me how I would feel if she was corrupted by Soul Edge to make her different and bring something new her character. I told her I would play her if this happened, but I would miss her attitude.
Once I bugged him after I found out that she was not going to be in SC5. He told me that his answer is not canon, but for me to consider her to be on a adventure during the events of SC5 and that she was not dead or the like, just "away".
Yeah, I bugged him a lot.
His answers did make me think that he wanted something to make Talim add more to the game if she came back, like introduce a new idea or mechanic or something, and this theme was common with most of his new characters. I am thinking later that I appreciate the sentiment, but does every character in the game add something entirely new or different? Meh. Just brainstorming here, I'm not even sure what I am trying to say.