I believe the current system is totally flawed when teams that win championships has 0 income all season or even go to minus, on the other hand tanking team can make millions for not playing and with current market situation, those teams can fast gain huge advantage against teams that has 0 income but which are fighting. BB is constantly rewarding "bad" behavior - be in the last place and you have the best draft pick, be in a 5th place and you don't have to pay salaries, I want to see "good" behavior to be rewarded.
Okay, this might slightly improve the situation for competitve teams, but you are not solving the problem. Tanking should be not possible or at very least - not profitable. Rewards will only make the top teams feel not deceived, whereas the goal is to make all teams competitive with equal chances.
Why they have 0 income? An example from my league from last season. League III, I had a well balanced team (salary at around $220k), not bad arena, income at around $0 (changing from plus to minus to plus every week). Finished 3rd in my conference, but sold my whole team just before play-offs. You ask why? Top teams fighting for league II had team salary reaching almost $500k. That's more than twice as much as mine. The result of this is: team with highest team salary got promotion, one team got bankrupt (and now seems like manager quit this game), other rearranged rosters and getting ready for the next play-offs. So when you see those numbers, it's no wonder they have no income, and by rewarding them you only help them to pay that monster salaries in their next play-off run.
It won't make it useless, because tanking teams will just buy better, multiskilled players.
Maybe the salary cap doesn't solve the problem completely, but it would even the chances against tanked teams. If the teams in my league in last season were capped at around $250k I could have clearly a shot there, but with teams with $500k? No chance, just a waste of time and money.
Also keep in mind that market is extremely limited on those players, it would very hard to buy one just before play-offs.