I had Blanca at the 3 and Serah at the 5 with the other obvious 3. I don't think Ash is an obvious 4th. She may well start, but for me the problem is the position. Is she the 4th best experienced proven returnee? Absolutely, but she is not a 3, rather a very good 2 that might be asked to play the 3. IMO none of the natural guards are a good fit at the 3.
I'm not saying the "guard" options at the 3 are weak, just not ideal for a true championship contender. Paige was unique and very different as mostly a 3 last year. She was great and very comfortable at that position, along with the 1 or 2, and was even very very good at the 4 the previous year, although there she was out of position. She could rebound better than most 3's and defend the position well.
None of the current guard options can rebound at a high level for a 3, or like a more natural 3 might. Of those choices Ash is the best small candidate, a significantly better rebounder than Azzi for example, but nowhere even close to what Paige was last year. If we go with a three guard lineup this year, it will truly be just that, while last year it may have been three guards, but one was easily able to rebound and defend at the 3.
Anyway Ash has done plenty in her time here, knows the system, and could start, I just don't consider it a given. You may gain other things, but you give up something too with a natural 2 at the 3. I think the three guard lineup is much better when one of those guards is bigger and can rebound and defend against natural 3's. We had that last year, this year we don't IMO, but we do have two talented natural 3's this year we didn't last year too.
Blanca and Caroline "could" be as good as Ash this season, and be playing their best position. I suspect Caroline as a starter is far more unlikely unless her availability becomes more assumed than day by day, but Blanca appears to have the talent and at least unique foreign experience to be a serious contender for the last spot.
While I picked and am hoping for Blanca to be so good that she keeps Ash as a super-sub, Ash could still get quite a few minutes behind Azzi and Blanca if that happened, with the small ball lineup still getting some play time. There even could be a much lower probability of a threat to Ash starting from the bigs. Not because they would play the 3, but rather most feel Sarah could be great at the 3, so if there are two great bigs for the 4 and 5 that could happen as well. If Jana had a major leap for example, she could man the 5, and I think Serah could easily slide over to the 4.
Somebody that is really really good is going to be left out of the starting lineup, and some that are still very good won't be in the main rotation. Regardless of who we think will start, it will be very interesting to see how it plays out.