You could also somewhat stratify by age the same as defense vs offense:
Successful development - Gray (22), O'Toole (25), Haak (23)
Unsuccessful development, stagnation, or regression - Magno (22), Fernandez (18), Ojeda (18), Mijatovic (18), Bakrar (23)
I know Magno and Bakar are similar in age but I wouldn't call either of their stagnations a development issue. Magno needs to be on the LW with a strong striker next to him to thrive. He failed when we took that from him, that's a team issue, not a development issue. Bakrar has some kind of hitch-like mental block that causes him to miss sitters, I'm not sure that's fixed by a coach either.
Development success is as much about the maturity and skillset of the player as it is about the coach. Perea looked like he belonged in the MLS the moment he stepped into a game. Fernandez, Ojeda, and Mijatovic often look like they are barely NYCFC II level, in fact, Ojeda, and Mijatovic both played full games with NYCFC II and neither of them stood out as noticeably more talented than the other players on the pitch nor did they make any goal or assist contributions. These players are extremely young and very raw and I honestly think the higher-ups at CFG that funneled them to us do not respect the quality of the MLS and they dumped these guys into a league they weren't ready for. They can still work out but the amount of development work it took to get Perea to where he was when he left compared to what it will take to make Jovan a successful MLS player is significantly different.
Also, a minor nitpick: we can't count Perea as a positive because he's only been here 1 year but we can count Fernandez, Ojeda, Mijatovic, and Bakrar as unsuccessful even though they have been with the team the exact same amount of time?
i think gabby was a baller from day 1. not sure he really developed under cushing.. just continued doing what he does. sad he went to saudi cause i was looking forward to seeing him with us for a while longer and then in europe.