The trade:
Cam Newton, Reggie Wayne, Vernon Davis
FOR
RG3, Kyle Rudolph
Your current team:
Cam Newton is averaging just over 21ppg, though inconsistent, over the best 4 of 5 games he has played so far. Reggie Wayne is averaging about 15ppg (if you exclude Week 3 vs. Jacksonville) but that is probably higher than you should expect him to average for the rest of the season. Vernon Davis is averaging about 11ppg so far (excluding Week 4) and that is the upper limit of where you should expect him to perform for the rest of the season.
The proposal:
RG3 is averaging just over 28ppg if you remove the week 5 performance vs. Atlanta that he left the game due to concussion. You can probably expect 25-30ppg through the rest of the season. Kyle Rudolph is averaging just over 10ppg if you discount the abysmal performance in Week 4 vs. Lions. This is probably the upper limit of where you should expect him to perform. Since the trade is 3 for 2 you would also have an extra spot on the roster for matchup-based pickups each week.
Conclusion: Although you might lose some points, if RG3 can continue to perform the way he has then this is a solid pick. As you said, Newton is not perfoming consistently. The Panthers have some offensive issues vs. the Redskins seem to have their offense pretty well under control. Also, Pierre Garcon is due back in the coming weeks which means an additional offensive weapon for RG3. Since it looks like you have a good handle on the WR position you can probably assume minimal impact and the TEs are comparable.
This is a close one but I think I would do it.
Check out my quandry:
http://forums.thehuddle.com/index.php?/topic/389540-maurice-jones-drew-deangelo-williams-robert-meachem-for-chris-johnson-stevan-ridley-dez-bryant/