I think it should be disabled altogether for human players but left in place for AI teams with a value system similar to what's currently there so those teams can participate in trade but avoid being fleeced.
As each league has a commish he should be the one that deals with any issues of collusion and he should have a tool box which lets him pause the countdown clock to the next sim and another option for him to reverse trades.
In the end we can't over regulate this and I think the FOF model worked for the most part.
Back in the day when I played OOTP baseball sims we had a cool rule in one of our leagues that obligated the GM in each deal to explain their rationale for doing deals which was extremely helpful to newer GMs. With this feature we never had a trade reversed and it all but eliminated guys dumping stars to their brother's team for 25 prospects.
The other thing to keep in mind is that some leagues might be a lot more scarce at certain positions. Right now in this league we have a ton of running backs with 90+ futures. Here that player is a superstar but not necessarily a franchise player.
However in a league where the top future is 74 for an RB, if one comes out with a 95 future that guy is a franchise player. Unless the trade system is accounting for this calculation in some way I think the automatic assignment of value will likely fall short.