Point being, if I've read it all correctly, the AI remains a bit too focused on the Active Roster for its potential acquisitions, notwithstanding prospects at lower levels that are often ignored as well unless initiated by the user in the trade.
There should exist more likelihood for exchanges between two teams of minor leaguers only. It does happen, though rarely, where teams exchange needs at farm positions to bolster potential for future starters. However, trying to initiate this kind of trade is still very unlikely to produce counter-offers that do not include someone from your current group of starters. That's simply unrealistic at all difficulty levels.
We've room for improvement in that area.