Campbell is an unknown, he hasn't played a down. He must look promising to Gibbs in practice or they would not be trying to move Ramsey. But until he plays it is anyone's guess.
If Campbell becomes just a functional QB, he will overall be the equal of Brunell fantasy-wise. Brunell has some good games but gets hurt and tails off in later games, having some truly bad ones.
I doubt Campbell can demonstrate enough knowledge and good judgement to be the opening day starter. I do think there's a decent possibility he'll be the starter by the end of the season, and certainly by the beginning of the following season. Just my guess from watching the Skins.
Lloyd should be a significant upgrade for Washington. It's hard to guess what fantasy numbers he will put up this year, since we don't know if it will be Brunell throwing accurately, Brunell bouncing passes, Campbell playing scared, or Campbell throwing rockets to Lloyd down the field. I'd say Lloyd has more fantasy value next year than this coming year.