I'd say whoever ends up with Jordan Matthews, Carlos Hyde, and Jeremy Maclin wins in terms of raw points.
However, the best player in that trade overall is likely McCoy. And D-Jax is a high risk, high reward guy, so it's tough to know where that WR grouping will end up.
My initial feeling was that the winner depends on where your WR corps is, if you can use the depth, the 2nd half wins, but if you need top end talent, especially at RB, then the 1st half wins.
That being said, I think Matthews has a really good chance to match up with D-Jax points-wise, as we've seen two top WRs (D-Jax and Maclin) succeed mightily in Chip Kelly's scheme. Matthews should be next in line to reap the benefits of the system, so he might be able to match up to D-Jax, or maybe even surpass him.
In that regard, the trade then becomes Jeremy Maclin for the difference between McCoy and Hyde. From a raw points standpoint, it's likely a good deal to send McCoy and D-Jax and get Matthews, McCoy, and Maclin in return.
The key question then, is will Maclin be starting in your lineup (I assume Matthews replaces D-Jax and Hyde replaces McCoy), and if so, is he enough of an upgrade over the currently slotted player to overcome the difference between McCoy and Hyde.
If yes, then it's a good trade. If not, you still might want to do it if the value is close, as you'll be adding a potentially starting caliber WR to your depth chart, and that's always a decent option.
In short, I'd probably do it, as again, from raw points, the latter three players should score more. But there are also situations where I can see someone declining, but that's based on your personal situation and roster.