I was thinking about this today, actually. (Yes, this is what I do with my free time).
Eliminating sign-and-trades could help teams keep their own free agents, assuming that teams could still offer their free agents more than outside teams can offer. Right now, sign-and-trades are used to circumvent that.
At the same time, this hurts teams that lose free agents. Currently, when a team loses a free agent, they can at least trade him for a trade exception and draft picks. Those trade exceptions can prove valuable when trying to bring in new talent. Eliminating that potentially makes it harder for teams to recover.
Of course, with a hard cap, the necessity of sign-and-trades almost disappears, as teams with cap space can sign guys, and teams without space can't.
I am against rules that help clubs keep their free agents because the flip side is that these are rules that hinder other clubs from signing free agents. This is an anti-parity rule.
Get rid of RFAs too. If you want to keep a guy, pay him. If this is supposed to be a reward for past investment, than lower the rookie scale. Why restrict a player's ability to get market value by playing games with their livelihood. If they want to keep the guy, sign him to an extension ahead of time instead of letting him become an RFA.
I completely disagree. Allowing teams to keep their free agents, or at least force other teams to compensate them for taking their free agents is absolutely a PARITY rule. If Toronto, Cleveland, Denver, and now New Orleans and Orlando had stronger measures in place to keep their best players, there would be a great deal more parity in the league.
Any league where individual free agents have more power to choose where they want to play than teams have in making their own personnel decisions (e.g. Melo deciding to be traded to NY and nowhere else; Bosh, Wade, and LeBron all planning to join up in 2010) is going to be a league without significant parity.
Right now, free agents have too much power and they have learned in the last few years just how much power they have. As a result, the league is becoming increasingly top-heavy.
Also, teams like the Thunder that draft well and manage their team well should be rewarded with the ability to hold onto the great core they put together. Otherwise, they're in danger of doing all the work of putting together a great team only to have it come apart because individual players want to be "the man" somewhere else, or want over-sized contracts that the small-market team can't afford.