FWIW, I generally hire good coaches for AAA and either HiA or LoA, and punt the rest of my coaching staff to save money. If I signed the IFA (I don't draft anymore) very early in the year, they play that year in Hia/LoA (wherever the good coach is) and then go to AAA the next. Otherwise, they finish their initial signing year in HiA/LoA, then a full year in HiA/LoA, then they go to AAA until I call them up.

Generally speaking, if somebody is a top prospect, they will be plenty dominant in AAA by their 2nd (full) year in the minors, so there won't be a problem with them getting lit up and losing development that way. If it's something like:

1st partial season: HiA/LoA
1st full season: HiA/LoA
2nd full season: AAA
3rd full season: AAA or majors

And after that, development is pretty limited anyway, so if they stay in a AAA holding pattern, it doesn't really matter anywyay.

Also, FWIW, I don't see the value of putting a player in AAA in his first partial season (ie, the season he is drafted/signed) because he will develop just as well in LoA. I might move him up to AAA in his 1st full season if I plan to promote him to the majors the next year, but it doesn't really make sense to drop him right into AAA, because it ruins your flexibiity and if you end up signing a guy in the majors that blocks him, I do think that you risk hindering development in his 3rd full season, which is still a fairly important one for development.