Can you say on what you base your assumptions, especially one that we wont see anything about Adolin till last 100k words ??
I like ADolin, I would like to see more of him, and at first your posts worried me, and then made me wonder if you know more them me or make false assumptions.
I read Reddit update, Sanderson answers and below is mine interpretation. It might be that I miss some piece of info, if thats the case, please give link
First, viewpoint dont mean character wont be showed in other parts of book or developed. It only mean that we see story from that character eyes.
We had a lot of Adolin development so far from povs of Shallan, Kaladin, Dalinar in WoK and WoR. Actually some of more important bits of Adolin's story were not through his eyes but from other characters (Adolin's helping prostitute in WoK, his dating with Shallan, parts of duel, aftermath of stay in prison to name few)
Second, like Overslept said, its Dalinar's book, so unless Adolin get separated from Dalinar, we might actually see more of him, not less if he will be around Dalinar.
Third, Sanderson said: " I am well aware that many people are very interested in what is happening to Adolin, and I consider him one of the more interesting and unexpected developments of the series, in deviation from the original outline. I intend to dig into things with him in the book."
So, in deviation from the original outline Sanderson will deepen Adolin's story, not make it shorter or shallower. I assume that original outline for Adolin was in place in WoK and most of WoR, so we actually might expect more of Adolin's story or richer story then previously.
All of above seems to indicate that Adolin's fans should be rather happy, not worried.