Ultimately, the idea behind all of these is to have an economy where the best players are paid top dollar and teams can afford them. This was also the idea behind the salary calibration that was introduced several seasons ago. While it's questionable whether the calibration is appropriate or not, the best players in the game currently cost about 90% of the income of a top division team. Technically speaking, it is possible to build a team around such a player by picking cheap role-players off the market -- though I guess what matters is that no-one has really tried to do it, so those guys still keep going around.
I've seen those guys going around. But somebody is still paying for their salaries, right? Or do they bankrupt every team that happens to have them on a Monday? There are many other threads in this forum filled with people complaining about daytraders and "rent-a-player" Cup games. I think the tools to keep the game fair are already there. They might not be realistic as in "Real-life NBA", but they are there.
Tradeline? BuzzerBeater makes money also by having users logging-in everyday and maybe clicking on their adds. A tradeline would keep them away from their computers for a while. It is better the way it is, with players not being able to play in the playoffs if they are bought too late in the season.
There's also an agency fee as high as 25% of the player's market value. You could buy a high-salary player to try to win a mid-week game, and then sell him before you even have to pay for his salary. True. But you would still lose 25% of the money you paid for him, not to consider the fact that if he gets injured you're never going to sell him that week.
The possibility of an injury is too high of a risk, I think.
Although, I've seen 450k-a-week players playing in division V.
Now that makes the game a little weird.
Should the salary be affected by the amount of money he was last traded for? Nah.
A player salary already depends on their market value: I've seen excellent players, with relatively low salaries, selling for a lot more than better players with higher unaffordable salaries. If you make a player salary go down just because the player was bought at a bargain price, then there will be a much higher profit for the team next time the player will be sold. A daytrader's dream come true.
I've heard of people wanting to put a cap on each individual player salary. I mean, if a player salary is so high that no team would want to pay it, then the player might just not play anymore. But as long as he is wanted, I guess it is fair for him to be around.
Still, I don't see who's paying for his salary on Monday. Somebody, please, let me understand what this fuzz is all about.