I think- and this is just what I think, absolutely nothing official- the main reason behind the training changes is a response to the community being so upset about the salaries of big men. The community has said time and again that the system is not working.
Players with ridiculous salaries have been a big sticking point on the forums. Recalculating salaries each season (another drop in wages this season- unmentioned I notice) is one way this has been tackled. These changes might, down the road, lead to slightly lower salaries for the behemoths.
1. I honestly don't think that you will notice a drastic change in your players unless your train them for many seasons. And if you do, perhaps you will be happy with their performance. Let's say you single position train a C for three seasons, rotating ID, IS, and REB 4 times and training stamina and FT once. Using the Training Speed Analysis you will have roughly 13.5 pops in ID and IS, 9 in REB, and a couple in driving and JS. So under the new system you would have 12.15 in ID and IS, 8.1 in REB, a couple in DR and JS, and about 4 pops spread around 10 skills. After three seasons.
2.see above.
3. Ask Mark Cuban about the value of older players. Older players are valuable because of their experience. Why should this be devalued?
Finally: a well-managed team is one that is flexible enough to know that changes happen all the time in this game. We were told about this at the beginning of last season.
Once I scored a basket that still makes me laugh.