The trade balance meter seems to be way out of line. There should be a significant reduction in value as players get older.
For example, I have a 12 year vet with an overall rating in the 90s. I would be willing to trade this player for a 4th rounder. However, the trade AI says it is weighted too much against me. In fact, it even says this for a 2nd rounder (the needle doesn't even budge). If I create the trade for this player for a 1st round pick, the balance bar is still weighted in the other team's favor, but it is allowable.
Nobody in their right mind would give up a 1st (or 2nd) for this guy, but I can't trade him otherwise.