Well we can't create a contract based and trading based transfer list. Because this would be uncontrollable and cheating friendly. We can limit daytrading (even if it's the resell tax) and high listing (which has not been done yet, perhaps a listing fee would be a thing to look at).
You know what would really ruin a new managers career? Buying a guy, realizing you made a mistake, and not being able to relist him until the following season.
Relisting the player will not get him his money back. Usually not even 1/3 of what he spent.
More restrictions on things = less abusers.
Obviously daytrading requires time and knowledge. It can be done by people who are online more, so it gives an advantage to a manager who is online more often (if BB's goal would be more online time then we should have live games with managers able to sub and take timeouts, true/false?). To me it destroys the natural process of building a team. With effective daytrading you can skip a lot of steps. But hey, that's just me. I have monitored a lot of teams and usually those teams get fined sooner or later. Daytrading is about buying low and selling high (not selling at normal). Plenty of teams have a bunch of their players listed at really high prices for weeks and weeks. They get bought really rarely and when they do it's like a jackpot for the manager (obviously there are restrictions of who can actually pull this off, like being in the higher league, divII for example and the buyer is in the lower league thinking the divII dude must have great players).
Took too long got bored:(