Great ideas, here are my thoughts:
Draft picks are not tradeable in real life, so why should they be in iOOTP? Maybe an option to turn on/off, but then we approach OOTP customization level
Compensation definitely needs to be fixed.
About the players on trade block before they get traded thing, the trade block is really only reserved for players the AI wants to get rid of. Lots of blockbuster deals are pulled with players that teams aren't actively shopping, like in real life. Also, wouldn't this limit you to only trading for players on the block?
And what do you mean by "batter type"? Like pull/spray hitter? I didn't even think that info was availible in iOOTP, only in OOTP. But maybe I'm wrong.
A side-suggestion to your development one, add the ability to learn a new position. Sometimes I'm forced to put high-rated 2B as 0-rated SS because of depth issues, but after a few years at short, they haven't gained a point.