I personally think this is the quickest way to ruin worlds when a new owner who doesn't know better gets convinced by a veteren to subsidise some salary in a trade because the veteren is doing the noob a favor. Or the cheating between two owners who just jack up someones money in trade after trade to the benefit of one team in a league.
What is the point in having a hard cap if we can manipulate it at will? As a solution that wouldn't radically change the way people do things the system could keep the 5 million max, however make the following changes:
1. 5 million in total can be traded outbound each season and 5 million could be received in total per season. This also would not count money received in a trade that would in effect wash the money sent away. 5 million is 5 million.
2. Allow money to be transferred only if the team that would be receiving it has NO MORE MONEYleft to transfer intermally. I know people would not like this but if we have a hard cap and you just have to have the 88 rated pitcher for 10 million a year, you should pay for it, not the other team. If he's not worth that much, then don't make the trade. If money is available then a pop up should come up informing the team that in order to complete the trade X number of dollars will be transferred from Prospects/Coaches and allow the team to comfirm the move.
3. Only allow the system to transfer money between teams on a per need basis, and ONLY to fit into a salary cap situation. Such as Team A trades Andy Adams (5.5 million x 3 years) to Team B and Team A receives Prospect Bob Baker (54k this season). Team B only had 3.5 million remaining in salary and did not have money to transfer from the prospect budget then the system should transfer enought money from Team A (1,946,000) to Team B in order to keep team B under the cap. Also the system should give the team who would have to transfer money one last time to confirm the transaction.
Please investigate this and if possible make it a priority. I haven't played as much as most of the others in this game, but I have seen 5 leagues screwed up because of money moving between teams.