I think if we got rid off Buy now and have Bid only, Squad Based Challenges and also what you get in packs as the only way to obtain getting players.
For example we have price ranges now which makes getting players either to cheap or at the same fixed price. For example you can have a player start bid at 650 and maximum 10k. If we got rid off the buy now.
We would only be able to win players by bidding and henceforth making the opportunity to make coins from sales. The downside would be you might have to spend more coins on some players (Because off others bidding a little more.) But better for everyone because the players will be worth more value than us frustrating selling them at 750 as a example.
The lowest bid starting price would have to increase for the best players. So if you wanted for example Dybala. Hes lowest start bid price would be 200k and you have to bid to win him.
For items like Contracts, Kits, Stadiums, Consumables, Managers etc etc will still have buy now. But not on players.