I wouldn't think of Ron as being purely a SF or swingman, I'd look at the team needs he fulfills. We had a similar problem when we replaced our big, Bonzi, with a swingman, and we shouldn't again confuse position with functionality.
Ron does a lot of middle to long range shooting, which can be made up for by Bibby, Kevin, or almost anyone but KT or Justin, so that's not a problem. What he contributes that IS in short supply, is defence, rebounding and inside presence. Salmons and Cisco are both decent defenders, and can help make up the loss somewhat, but we lose using either one, they just aren't at the same level. For our defence to be even close to the level it was at, we need to deal with the problems at PF/C (which would also address the deficiencies in our rebounding and inside game). The lane is usually wide open, and Piksi's suggestion that we clog it up with trees probably wouldn't sit well with the NBA.
Since GP failed to do anything by the trade deadline, this means either pulling a miraculous FA rabbit out of a hat, which seems extremely improbable, or putting Justin in a lot more. Sure, he will make dumb rookie mistakes, but that's going to happen any time we start playing him, and it may as well be now. It's not as if we have a championship on the line, this is the garbage time of our season. And he'll get better.