1) I think they are using "the drops" for doing the same, but I can relate to your idea.
I think they need to use both, as they are both happen in "real" basketball, and are affecting the team totaly differently.
2) I agree with you to a point.
I've already posted a similar suggestion two days age.
I believe that the coach needs to get definitions for the requested minutes (min and max) and to work to fulfil it.
Of course he has other parameters for minutes spreading, but adding this request is more than reasonable.
I've also heard the slogan "minutes spreading is one of the hardest and main task in this game", and I don't see it the same.
The user already has the ability to control the minutes (up to a point) by defining who is the starter and who is a backup.
In addition, there is the definition of the depth chart usage.
A situation that a coach gives the backup more minutes than the started due to garbage time, and hence messing up with your commands, is not "normal". Especially if the backup already has more than enough minutes.
3) It is kind of a free market. there is no reason why not letting the users to ask for a ridicules price.
On the other hand, there is a chance that a user will bid mistakenly due to missreading the value as it wiill fill like unreasonable value and unconciously he will think they meant a smaller amount of price.
To solve this I suggest to write the price using words and not numbers.
I guess the last one is a new suggestion...